CN101232265A - Current-limiting protection control structure for reducing motor switching noise - Google Patents

Abstract

The invention relates to a current-limiting protection control structure for reducing switching noise of a motor, which mainly comprises: a motor winding; a driving unit electrically connected to the motor windings for driving the motor formed by the motor windings to operate; the sensing unit is electrically connected with the motor winding, detects the driving level flowing through the motor winding, compares the preset reference level of the sensing unit according to the driving level and outputs an identification signal; and the control unit is electrically connected with the driving unit, the sensing unit and the Hall assembly, and adjusts the driving level of the driving unit output to the motor winding according to the identification signal output by the sensing unit so that the output of the driving unit still maintains a basic working period.

Description

Current-limiting protection control structure to reduce motor switching noise

technical field

The present invention relates to a control structure, and in particular relates to a method of limiting the driving voltage level of the motor to prevent the noise generated during its operation.

Background technique

The general existing technology is to use pulse width modulation signal (hereinafter referred to as PWM signal) to control the conduction time of the coil winding in the cooling fan motor to control the rotation of the cooling fan motor, and according to the different duty cycles of the PWM signal (hereinafter referred to as DUTYCYCLE). To achieve the purpose of controlling different rotational speeds, variables such as the amplitude, frequency and duty cycle (DUTYCYCLE) of the PWM signal of the aforementioned technology will all affect the rotational speed of the fan motor.

Furthermore, please refer to FIG. 1, which is a first type of existing circuit, as shown in the figure, it includes a reverse voltage protection diode 101, a Hall element 102, a driving element 103, a first transistor 104, a second transistor 105, and a first resistor 106. , the second resistor 107, the third resistor 108 and the first motor winding 109, the second motor winding 120, the fourth resistor 121, the fifth resistor 122 and the third transistor 123, the fourth transistor 124, the Hall component 102 , the driving component 103 , the first transistor 104 , the second transistor 105 , the first resistor 106 , the second resistor 107 , the third resistor 108 , the first motor winding 109 , and the second motor winding 120 form the driving circuit 10 .

When the power supply is turned on and applied to the circuit through the reverse voltage protection diode 101, the Hall component 102 of the driving circuit 10 detects the change of the magnetic pole of the rotor and generates positive voltage H+ and negative voltage H- to output to the driving component 103. The above-mentioned voltage is converted into a control signal source and output to the first transistor 104 and the second transistor 105 through the first output terminal OUT1 and the second output terminal OUT2, and a pulse width modulation signal input terminal PWM passes through the fourth resistor 121 and the fifth resistor 122 and the collector of the third transistor 123 and the fourth transistor 124, cut off the control signal source of the first output terminal OUT1 and the second output terminal OUT2 of the driving component 103, so as to control the collector connected to the first transistor 104 and the second transistor 105 The first motor winding 109 and the second motor winding 120 are used to control the variation of the rotation speed of the fan motor.

Please refer to FIG. 2 for the second existing circuit, as shown in the figure, it includes a reverse voltage protection diode 201, a Hall element 202, a drive element 203, a first transistor 204, a second transistor 205, a first resistor 206, The second resistor 207, the third resistor 208, the first motor winding 209, the second motor winding 220, the fourth resistor 221, and the third transistor 222, wherein the Hall component 202, the drive component 203, and the first transistor 204 , the second transistor 205, the first resistor 206, the second resistor 207, the third resistor 208, the first motor winding 209, and the second motor winding 220 form the driving circuit 20, and a pulse width modulation signal input terminal PWM passes through the fourth The resistor 221 and the third transistor 222 are connected to the control input terminal ST of the driving component 203, through the periodic change of the pulse width modulation signal, the duty cycle (DUTYCYCLE) of the pulse modulation signal is changed to control the driving circuit 20 to generate switch actuation time to control The power supply of the first motor winding 218 and the second motor winding 219 controls the change of the rotation speed of the fan motor.

Please refer to FIG. 3 again for a third existing circuit, as shown in the figure, a reverse voltage protection diode 301, a Hall component 302, a driving component 303, a first transistor 304, a second transistor 305, a first resistor 306, a second The resistor 307, the third resistor 308, the first motor winding 309, and the second motor winding 320 form the drive circuit 30, and a pulse width modulation signal input terminal PWM controls the on and off of the input power through the fourth resistor 321 and the third transistor 322. , driving the first motor winding 309 and the second motor winding 320 connected to the collectors of the first transistor 304 and the second transistor 305 to control the rotation speed of the fan motor.

Please refer to FIG. 4 first, which shows the corresponding waveforms per unit time between the PWM signal and the current (hereinafter referred to as the winding current) passing through the aforementioned motor windings (ie, the first motor winding 309 and the second motor winding 320 ) in the prior art. However, when the above-mentioned prior art needs to limit the level of current flowing through the aforementioned motor windings according to various applications, the 25kHz PWM signal is turned off due to the activation of the current limiting protection function of the drive component until the aforementioned winding current is lower than the predetermined level. However, in this way, multiple 25kHz PWM signals will disappear, causing the PWM frequency to be reduced below 20kHz, and motor switching noise will be generated. Therefore, it is necessary to improve the shortcomings of the prior art.

Contents of the invention

The main purpose of the present invention is to provide a current limiting protection control structure that reduces motor switching noise, and can adjust the driving level of the motor by setting the reference level of the sensing unit to achieve the desired fan motor speed. The range of value and rotational speed.

The second object of the present invention is to provide a current limiting protection control structure that reduces motor switching noise, and uses the identification signal output by the sensing unit to limit the driving level of the motor, so that the control unit can change the driving level of the motor or/and work. Cycle (DUTYCYCLE), in order to avoid the frequency change of the motor operation frequency wide modulation signal, which will cause the human ear to sense the noise.

In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a current-limiting protection control structure for reducing motor switching noise, which mainly includes: a motor winding; a drive unit, which is electrically connected to the above-mentioned motor winding. Driving the motor formed by the motor winding; a sensing unit is electrically connected to the motor winding, detects the driving level flowing through the motor winding and compares it with the preset reference level of the sensing unit and outputs Identification signal; a control unit is electrically connected to the above-mentioned driving unit, the aforementioned sensing unit and a Hall assembly, and the control unit adjusts the driving level output from the above-mentioned driving unit to the aforementioned motor winding according to the identification signal output by the sensing unit bit, so that the output of the drive unit still maintains a basic duty cycle.

The "current limiting protection control structure for reducing motor switching noise" provided by the present invention has the following advantages:

1. Adjust the drive level of the motor by setting the reference level of the sensing unit to achieve the fan motor speed value and the range of speed change that you want to set, and greatly reduce the error caused by the frequency change of the pulse width modulation signal , resulting in fan motor rotation speed deviation, that is, greatly reducing the fan motor rotation speed is affected by changes in the duty cycle (DUTYCYCLE) of the pulse width modulation signal.

2. Use the sensing unit to detect the driving level of the motor and output a discrimination signal, so that the control unit can maintain a minimum duty cycle when changing the driving motor level, so as to ensure that the current limiting protection function is transmitted to the drive unit 20 The PWM signal will not be low at 25kHz and cause noise that can be sensed by the human ear.

Description of drawings

Fig. 1 is the schematic diagram of the first kind of existing circuit;

Fig. 2 is a schematic diagram of the second existing circuit;

Fig. 3 is the schematic diagram of the third existing circuit;

Fig. 4 is a prior art PWM signal and a schematic diagram of the waveform passing through the aforementioned motor winding;

Fig. 5 is a schematic circuit diagram of a feasible embodiment of the present invention;

Fig. 6 and Fig. 7 are feasible circuit schematic diagrams of the present invention;

FIG. 8 is a schematic diagram of the PWM signal of the present invention and the waveform passing through the aforementioned motor winding.

Explanation of reference numerals: 10-motor winding; 11-first motor winding; 12-second motor winding; 20-drive unit; 30-sensing unit; 31-first resistance; 32-second resistance; 33-third Resistor; 40—control unit; 41—first pulse width modulation output terminal; 42—second pulse width modulation output terminal; 50—Hall component; 60—power supply.

Detailed ways

For other advantages, purposes, technical features and effects of the present utility model, it is a detailed description of the preferred embodiments of the case that can be matched with the drawings below.

Please refer to FIG. 5 (other drawings can be referred to together), which shows a feasible embodiment of the "current limiting protection control structure for reducing motor switching noise" of the present invention, which mainly includes: a motor winding 10 (the motor formed by the aforementioned winding 10) (not shown in the figure) can be a single-phase, two-phase, three-phase motor); a driving unit 20 is electrically connected to the above-mentioned motor winding 10 to drive the operation of the motor formed by the above-mentioned motor winding 10; a sensing unit 30 is Electrically connect the motor winding 10 (or set in the motor), detect the driving level (current or/and voltage) flowing through the motor winding 10 and compare it with the preset reference level of the sensing unit 30 bit (can be set or adjusted by the user or during production), and can output a discrimination signal according to the comparison result.

A control unit 40 is to electrically connect the above-mentioned driving unit 20, the aforementioned sensing unit 30 and a Hall component 50 (and the aforementioned units or components can be electrically connected to a power supply 60 to obtain the energy required for actuation), not only The positive voltage H+ and negative voltage H- signals are generated by receiving the magnetic pole change detected by the Hall component 50 when the motor is running, and the output of the driving unit 20 can be adjusted according to the identification signal output by the sensing unit 30. The driving level of the aforementioned motor winding 10 is to limit the variation of the rotational speed of the motor winding 10 within a certain range, and to maintain a minimum duty cycle (such as 5% PWM signal pulse width) of the driving unit 20, so Keep the frequency of motor switching noise not lower than 25kHz, which can be sensed by the human ear, so the noise during motor speed switching can be greatly reduced. Please refer to Figures 6 and 7 (other figures can be referred to) to show a feasible application circuit structure (but not limited to this), the control unit 40 has a first pulse width modulation output terminal 41. A second pulse width modulation output terminal 42 is to respectively provide the input of the pulse width modulation signal (hereinafter referred to as the PWM signal, please refer to FIG. 8 ) of the above-mentioned driving unit 20; In (DUTYCYCLE), the drive unit 20 is driven to keep driving the motor winding 10 (including a first motor winding 11 and a second motor winding 12 shown in the figure) and the motor runs.

That is to say, the present invention can not only simply adjust the preset reference level of the sensing unit 30 to limit the driving level (current or/and voltage) flowing through the aforementioned motor winding 10, for example: change in FIG. 6 and FIG. 7 The resistance values of a first resistor 31 and a second resistor 32 of the sensing unit 30 can obtain different ratios of voltage division effects, and then achieve the function of setting or changing the preset reference level, and can also Make the control unit 40 display only when it receives the discrimination signal from the sensing unit 30 (the output signal of the sensing unit 30 after comparing the preset reference level with the drive level flowing through the aforementioned motor winding 10) The current limiting protection function is activated only when the driving level formed by the third resistor 33 of the sensing unit 30 is not less than the preset reference level of the sensing unit 30 by the current (or winding current) flowing through the aforementioned motor winding 10 (Adjust or limit the driving level of the above-mentioned drive unit 20 output to the above-mentioned motor winding 10), which can change the prior art because of the current limiting protection. disappear, causing its PWM frequency to be reduced below 20kHz), therefore, the control unit 40 of the present invention will make the drive unit 20 still maintain a basic duty cycle (for example, 5% PWM signal pulse width, but not with this In this way, the switching noise frequency of the motor will not be lower than the human ear can sense the range of 25kHz, so the noise can be greatly reduced.

This invention has not been disclosed and used, and it also meets the requirements of an invention patent. An application is filed in accordance with the law. I sincerely ask for the grant of a patent, which is what I look forward to.

The above description is only a preferred embodiment of the present case. The aforementioned steps do not represent the implementation sequence, and are not intended to limit the present invention. Such changes, modifications and applications, as well as the resulting equivalent effects, shall be included in the scope of rights of this case.

Claims (4)

1. current limiting protection control structure that reduces motor switch noise, it is characterized in that: it includes: a motor winding;

One driver element is to be electrically connected the said motor winding, to drive the motor operation that aforementioned motor winding is constituted;

One perception unit is to be electrically connected described motor winding, detects accurate of the preset reference and the output distinguishing signal of the accurate position of driving and the more described according to this perception unit of the aforementioned motor winding of flowing through;

One control unit, be to be electrically connected above-mentioned driver element, aforementioned perception unit and a Hall subassembly, and described control unit is adjusted the accurate position of driving that above-mentioned driver element exports aforementioned motor winding to according to the distinguishing signal of described perception unit output, and described driver element output is still kept a basic work period.

2. the current limiting protection control structure of reduction motor switch noise according to claim 1 is characterized in that: described Hall subassembly and described control unit are to be integrated in an integrated circuit.

3. the current limiting protection control structure of reduction motor switch noise according to claim 1 is characterized in that: described driver element, Hall subassembly and described control unit are to be integrated in an integrated circuit.

4. the current limiting protection control structure of reduction motor switch noise according to claim 1 is characterized in that: described driver element, aforementioned perception unit, Hall subassembly and described control unit are to be integrated in an integrated circuit.

Images