Adjustable voltage circuit and its control method, motor drive device

Abstract

This invention discloses an adjustable voltage circuit and its control method, as well as a motor drive device, belonging to the field of power supply circuit technology. The adjustable voltage circuit includes: a voltage divider module for dividing the power supply voltage provided by the power supply terminal and outputting a divided voltage; an impedance module; at least one of the voltage divider module and the impedance module includes a variable resistor, making the divided voltage and / or the impedance of the impedance module adjustable; an electrical signal conditioning module for determining the voltage output by the electrical signal conditioning module based on the divided voltage, and determining the current output by the electrical signal conditioning module based on the impedance of the impedance module; an output module for controlling the supply voltage output by the voltage output terminal based on the output voltage and current of the electrical signal conditioning module; and a control module for adjusting the resistance value of at least one variable resistor based on the difference between the supply voltage and a preset voltage. Embodiments of this invention can provide an adjustable supply voltage, improving the versatility of the motor drive device.

Description

Technical Field

[0001] This invention relates to the field of power supply circuit technology, and in particular to an adjustable voltage circuit and its control method, and a motor drive device. Background Technology

[0002] With the widespread adoption of variable frequency motors, corresponding motor drive boards have also developed. During operation, these drive boards need to output a motor speed signal, the amplitude of which is determined by the power supply connected to the drive board. In practical applications, different motors require different motor speed signal amplitudes, necessitating customized power supplies for the drive boards. This results in a limited range of motor types that the drive device can drive, leading to poor versatility. Summary of the Invention

[0003] This invention provides an adjustable voltage circuit and its control method, as well as a motor drive device, to provide an adjustable power supply voltage and improve the versatility of the motor drive device.

[0004] In a first aspect, embodiments of the present invention provide an adjustable voltage circuit, comprising:

[0005] A voltage divider module is connected between the power supply terminal and the ground terminal; the voltage divider module is used to divide the power supply voltage provided by the power supply terminal and output the divided voltage.

[0006] An impedance module, wherein a first terminal of the impedance module is connected to the power supply terminal; wherein at least one of the voltage divider module and the impedance module includes a variable resistor, such that the voltage divider voltage and / or the impedance of the impedance module are adjustable;

[0007] An electrical signal conditioning module is connected to the output terminal of the voltage divider module, the second terminal of the impedance module, the power supply terminal, and the voltage output terminal, respectively. The electrical signal conditioning module is used to determine the output voltage of the electrical signal conditioning module based on the voltage divider voltage, and to determine the output current of the electrical signal conditioning module based on the impedance of the impedance module.

[0008] An output module is connected to the output terminal of the electrical signal conditioning module, the ground terminal, and the voltage output terminal, respectively; the output module is used to control the supply voltage output by the voltage output terminal according to the output voltage and current of the electrical signal conditioning module.

[0009] A control module is connected to the voltage output terminal and each of the variable resistors; the control module is used to adjust the resistance value of at least one of the variable resistors according to the difference between the supply voltage and the preset voltage.

[0010] Optionally, the voltage divider module includes: a first resistor and a first digital potentiometer;

[0011] The first end of the first resistor is connected to the power supply terminal, the second end of the first resistor is connected to the first end of the first digital potentiometer and the electrical signal adjustment module, the second end of the first digital potentiometer is connected to the ground terminal, and the control terminal of the first digital potentiometer is connected to the control module; wherein, the first digital potentiometer serves as a variable resistor in the voltage divider module.

[0012] Optionally, the impedance module includes: a second digital potentiometer, a first terminal of which is connected to the power supply terminal, a second terminal of which is connected to the electrical signal conditioning module, and a control terminal of which is connected to the control module; the second digital potentiometer serves as a variable resistor in the impedance module.

[0013] or,

[0014] The impedance module includes a second resistor, which is connected between the power supply terminal and the electrical signal conditioning module.

[0015] Optionally, the resistance value of the first digital potentiometer is between 0.1 and 1.25 times the resistance value of the first resistor.

[0016] Optionally, the electrical signal conditioning module includes:

[0017] The first transistor has its base connected to the output terminal of the voltage divider module, its collector connected to the second terminal of the impedance module, and its emitter connected to the output module.

[0018] The second transistor has its base connected to the collector of the first transistor, its emitter connected to the power supply terminal, and its collector connected to the voltage output terminal.

[0019] The output module includes:

[0020] The third resistor is connected between the output terminal of the electrical signal conditioning module and the ground terminal;

[0021] A fourth resistor is connected between the output terminal of the electrical signal conditioning module and the voltage output terminal. Optionally, the first transistor is an NPN transistor, and the second transistor is a PNP transistor.

[0022] And / or,

[0023] The current amplification factor of both the first transistor and the second transistor is greater than 10^4.

[0024] Optionally, the adjustable voltage circuit further includes: a sampling module connected between the voltage output terminal and the ground terminal; the sampling module is used to sample the supply voltage and output the sampled supply voltage;

[0025] The control module is connected to the output terminal of the sampling module. The control module is used to adjust the resistance value of at least one of the variable resistors according to the difference between the sampling power supply voltage and the sampling preset voltage; wherein, the sampling preset voltage is equal to the sampling power supply voltage corresponding to the preset voltage.

[0026] Optionally, the sampling module includes a fifth resistor and a sixth resistor; the first end of the fifth resistor is connected to the voltage output terminal, the second end of the fifth resistor is connected to the control module and the first end of the sixth resistor respectively, and the second end of the sixth resistor is connected to the ground terminal.

[0027] Secondly, embodiments of the present invention also provide a control method for an adjustable voltage circuit, applied to an adjustable voltage circuit provided in any embodiment of the present invention, and executed by a control module; the control method for the adjustable voltage circuit includes:

[0028] Obtain the supply voltage output from the voltage output terminal of the adjustable voltage circuit;

[0029] When the difference between the supply voltage and the preset voltage does not meet the preset difference, the resistance value of at least one variable resistor in the adjustable voltage circuit is adjusted according to the relationship between the supply voltage and the preset voltage until the difference between the supply voltage and the preset voltage meets the preset difference.

[0030] Thirdly, embodiments of the present invention also provide a motor drive device, comprising: a motor drive board and an adjustable voltage circuit provided according to any embodiment of the present invention, wherein the motor drive board is connected to a motor and the adjustable voltage circuit respectively.

[0031] The adjustable voltage circuit provided in this embodiment of the invention includes a voltage divider module, an impedance module, an electrical signal adjustment module, an output module, and a control module. At least one of the voltage divider module and the impedance module includes a variable resistor controllable by the control module, enabling the adjustable voltage circuit to perform programmable voltage regulation. Specifically, after determining the preset output voltage required by the adjustable voltage circuit, the control module can control the resistance value of at least one connected variable resistor based on the difference between the actual output supply voltage and the preset voltage. This adjusts the voltage divided by the voltage divider module and / or the impedance of the impedance module, thereby regulating the voltage and / or current output by the electrical signal adjustment module, bringing the supply voltage closer to the preset voltage and realizing the voltage regulation function of the adjustable voltage circuit. In summary, by providing an adjustable voltage circuit with an adjustable supply voltage, this embodiment of the invention enables the motor drive device to drive more types of motors, improving the versatility of the motor drive device.

[0032] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of an adjustable voltage circuit provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of another adjustable voltage circuit provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of another adjustable voltage circuit provided in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of another adjustable voltage circuit provided in an embodiment of the present invention;

[0038] Figure 5 This is a flowchart illustrating a control method for an adjustable voltage circuit provided in an embodiment of the present invention;

[0039] Figure 6 This is a schematic diagram of the structure of a motor drive device provided in an embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0042] This invention provides an adjustable voltage circuit that can be applied to a motor drive device. By providing an adjustable power supply voltage, the motor drive board in the motor drive device can support the output of various motor speed signals with different amplitudes, thereby improving the versatility of the motor drive device. Figure 1 This is a schematic diagram of an adjustable voltage circuit provided in an embodiment of the present invention. See also... Figure 1 The adjustable voltage circuit includes: a voltage divider module 10, an impedance module 20, an electrical signal adjustment module 30, an output module 40, and a control module 50.

[0043] The adjustable voltage circuit may include a power supply terminal, a ground terminal, and a voltage output terminal. The power supply terminal is connected to the power supply voltage VCC, the ground terminal is connected to the ground signal GND, and the voltage output terminal outputs the supply voltage VOUT. The power supply voltage VCC can be used as the positive power supply signal in the adjustable voltage circuit, and the ground signal GND can be used as the negative power supply signal. In this adjustable voltage circuit, a voltage divider module 10 is connected between the power supply terminal and the ground terminal. The voltage divider module 10 is used to divide the power supply voltage VCC provided by the power supply terminal and output a divided voltage V1. The first terminal of the impedance module 20 is connected to the power supply terminal. At least one of the voltage divider module 10 and the impedance module 20 includes a variable resistor, so that the divided voltage V1 and / or the impedance of the impedance module 20 are adjustable. The electrical signal conditioning module 30 is connected to the output terminal of the voltage divider module 10, the second terminal of the impedance module 20, the power supply terminal, and the voltage output terminal, respectively. The electrical signal conditioning module 30 is used to determine the voltage output by the electrical signal conditioning module 30 according to the divided voltage V1, and to determine the current output by the electrical signal conditioning module 30 according to the impedance of the impedance module 20. Output module 40 is connected to the output terminal, ground terminal, and voltage output terminal of electrical signal conditioning module 30, respectively; output module 40 is used to control the supply voltage VOUT output by voltage output terminal according to the voltage and current output by electrical signal conditioning module 30. Control module 50 is connected to voltage output terminal and each variable resistor, respectively; control module 50 is used to adjust the resistance value of at least one variable resistor according to the difference between supply voltage VOUT and preset voltage.

[0044] For example, when the voltage divider module 10 has a variable resistor, by adjusting the resistance value of the variable resistor in the voltage divider module 10, specifically by controlling the resistance value of the variable resistor connected to the voltage divider module 10, the voltage division effect of the voltage divider module 10 on the power supply voltage VCC can be changed, making the divided voltage V1 adjustable. For example, the proportional relationship between the impedance between the power supply terminal and the output terminal of the voltage divider module 10 and the impedance between the ground terminal and the output terminal of the voltage divider module 10 can be changed, thereby changing the value of the divided voltage V1 output by the output terminal of the voltage divider module 10. Therefore, when the voltage divider module 10 has a variable resistor, the control module 50 can change the value of the divided voltage V1 by changing the resistance value of the variable resistor in the voltage divider module 10, thereby changing the voltage output by the electrical signal adjustment module 30, and further changing the power supply voltage VOUT output by the output module 40. For example, the voltage divider module 10 may have a resistive voltage divider structure.

[0045] When the impedance module 20 has a variable resistor, the impedance of the impedance module 20 can be adjusted by changing the resistance value of the variable resistor connected to the impedance module 20. Therefore, when the impedance module 20 has a variable resistor, the control module 50 can change the impedance of the impedance module 20 by changing the resistance value of the variable resistor, thereby changing the current output by the electrical signal adjustment module 30, and consequently changing the supply voltage VOUT output by the output module 40.

[0046] It is understandable that in an adjustable voltage circuit, such as Figure 1 As shown, both the voltage divider module 10 and the impedance module 20 have variable resistors. Based on this, the control module 50 can adjust the supply voltage VOUT by adjusting the resistance value of the variable resistors in the voltage divider module 10 and / or the impedance module 20. Alternatively, in the adjustable voltage circuit, only the voltage divider module 10 may have a variable resistor; in this case, the control module 50 can adjust the supply voltage VOUT by adjusting the resistance value of the variable resistor in the voltage divider module 10. Furthermore, in the adjustable voltage circuit, only the impedance module 20 may have a variable resistor; in this case, the control module 50 can adjust the supply voltage VOUT by adjusting the resistance value of the variable resistor in the impedance module 20.

[0047] The electrical signal conditioning module 30 may include an integrated chip or signal processing chip with transistor characteristics, as long as it can adjust the voltage and current output by the output terminal of the electrical signal conditioning module 30 according to the input voltage and input impedance. The specific structure of the electrical signal conditioning module 30 is not limited here.

[0048] The output module 40 may include impedance elements to convert the input voltage and current to obtain the supply voltage VOUT. The connection relationship of the impedance elements in the output module 40 is not limited here.

[0049] The control module 50 may include controllers such as MCU (Microcontroller Unit), FPGA (Field Programmable Gate Array), or single-chip microcomputer, as well as peripheral circuits required for the controller to operate.

[0050] Understandable, Figure 1The example provided illustrates an implementation where both the voltage divider module 10 and the impedance module 20 include variable resistors, but this is not intended to limit the invention. In other embodiments, only the voltage divider module 10 or only the impedance module 20 may have variable resistors. Exemplarily, the variable resistor is an electrically controlled adjustable resistor with a control terminal, so that its resistance value can be controlled by the control module 50. Based on any of the above embodiments, the control module 50 can be connected to all the variable resistors provided in the adjustable voltage circuit to control the supply voltage VOUT by adjusting the resistance values ​​of the variable resistors.

[0051] In this adjustable voltage circuit, the control module 50 can change at least one of the voltage and current output by the electrical signal conditioning module 30 by changing the resistance value of at least one of the variable resistors connected to it, thereby changing the supply voltage VOUT output by the output module 40 and realizing the adjustability of the supply voltage VOUT. The preset voltage can be the supply voltage required for the operation of the device to be powered (e.g., a motor drive board), and different devices to be powered may have different preset voltages. After the preset voltage is determined, the control module 50 can adjust the resistance value of the connected variable resistors according to the difference between the supply voltage VOUT output by the adjustable voltage circuit and the preset voltage until the difference between the supply voltage VOUT and the preset voltage enters the allowable difference range of the supply voltage of the device to be powered, thus completing the regulation of the adjustable voltage circuit. When supplying power to the device to be powered subsequently, the resistance values ​​of each variable resistor can be kept constant to ensure that the output of the adjustable voltage circuit meets the needs of the device to be powered.

[0052] The adjustable voltage circuit provided in this embodiment of the invention includes a voltage divider module 10, an impedance module 20, an electrical signal adjustment module 30, an output module 40, and a control module 50. At least one of the voltage divider module 10 and the impedance module 20 includes a variable resistor controllable by the control module 50, enabling the adjustable voltage circuit to have a programmable voltage regulation function. Specifically, after determining the preset voltage to be output by the adjustable voltage circuit, the control module 50 can control the resistance value of at least one connected variable resistor based on the difference between the actual output supply voltage VOUT and the preset voltage. This adjusts the voltage divider voltage V1 output by the voltage divider module 10 and / or adjusts the impedance of the impedance module 20, thereby regulating the voltage and / or current output by the electrical signal adjustment module 30, making the supply voltage VOUT approach the preset voltage, thus realizing the voltage regulation function of the adjustable voltage circuit. In summary, by providing an adjustable voltage circuit with an adjustable supply voltage VOUT, this embodiment of the invention enables the motor drive device to drive more types of motors, improving the versatility of the motor drive device.

[0053] The following description provides an example of the possible circuit structures of each functional module in the adjustable voltage circuit, but this is not intended to limit the invention.

[0054] Figure 2 This is a schematic diagram of another adjustable voltage circuit provided in an embodiment of the present invention. See also... Figure 2 In one embodiment, optionally, the voltage divider module 10 includes: a first resistor R1 and a first digital potentiometer DCP1. The first end of the first resistor R1 is connected to the power supply terminal, and the second end of the first resistor R1 is connected to both the first end of the first digital potentiometer DCP1 and the output terminal of the voltage divider module 10. The output terminal of the voltage divider module 10 is connected to the electrical signal adjustment module 30. The second end of the first digital potentiometer DCP1 is connected to the ground terminal, and the control terminal of the first digital potentiometer DCP1 is connected to the control module 50. Figure 2 The connection relationship is not shown in the figure; please refer to [reference needed]. Figure 1 The first digital potentiometer DCP1 serves as a variable resistor in the voltage divider module 10.

[0055] In the voltage divider module 10, a voltage is obtained by dividing the voltage between the first resistor R1 and the first digital potentiometer DCP1. The first resistor R1 is a resistor with a fixed resistance value, while the resistance value of the first digital potentiometer DCP1 is adjustable. For example, the first digital potentiometer DCP1 can be constructed using any type of digital potentiometer; a digital potentiometer can also be called a digital resistor. A digital potentiometer includes a digital potentiometer chip, which is an integrated circuit (IC) composed of multiple precision resistors connected in series, with a tap contact between every two precision resistors. This digital potentiometer chip can receive digital control signals via IIC (Integrated Circuit Communication Protocol), then decode the digital control signals, and determine the selection contact position based on the decoded signals, thereby achieving precise control of the resistance value. Based on the above principle, the control module 50 can control the resistance value of the first digital potentiometer DCP1 connected in series with the first resistor R1 in the voltage divider module 10.

[0056] See also Figure 2 Based on the above embodiments, optionally, the impedance module 20 includes: a second digital potentiometer DCP2; the first terminal of the second digital potentiometer DCP2 serves as the first terminal of the impedance module 20, connected to the power supply terminal, and connected to the power supply voltage VCC; the second terminal of the second digital potentiometer DCP2 serves as the second terminal of the impedance module 20, connected to the electrical signal adjustment module 30; the control terminal of the second digital potentiometer DCP2 is connected to the control module; and the second digital potentiometer DCP2 serves as a variable resistor in the impedance module 20. For example, the second digital potentiometer DCP2 can be constructed using any type of digital potentiometer. The structure and function of digital potentiometers can be found in the above explanation and will not be repeated here.

[0057] The above embodiments illustrate one implementation of the voltage divider module 10 and the impedance module 20. For example... Figure 2As shown, both the voltage divider module 10 and the impedance module 20 have variable resistors, which allows for a wider adjustment range of the supply voltage VOUT. However, the above embodiments are not intended to limit the invention. In other embodiments, the impedance module 20 may include a second resistor connected between the power supply terminal and the electrical signal conditioning module 30. The second resistor is a resistor with a fixed resistance value, which is equivalent to setting the impedance of the impedance module 20 to be fixed, with only the voltage divider module 10 having a variable resistor, thus simplifying the control logic of the control module 50. Alternatively, the first digital potentiometer DCP1 in the voltage divider module 10 may be replaced with a resistor with a fixed resistance value, so that only the impedance module 20 has a variable resistor, thereby simplifying the control logic of the control module 50.

[0058] See also Figure 2 Based on the above embodiments, optionally, the electrical signal conditioning module 30 includes: a first transistor Q1 and a second transistor Q2; wherein, the base of the first transistor Q1 is connected to the output terminal of the voltage divider module 10, the collector of the first transistor Q1 is connected to the second terminal of the impedance module 20, and the emitter of the first transistor Q1 serves as the output terminal of the electrical signal conditioning module 30, connected to the output module 40; the base of the second transistor Q2 is connected to the collector of the first transistor Q1, the emitter of the second transistor Q2 is connected to the power supply terminal, and the collector of the second transistor Q2 is connected to the voltage output terminal.

[0059] In this circuit, both transistors Q1 and Q2 operate in the linear region, and the voltage between their bases and emitters is stable. Therefore, transistor Q1 can determine its emitter voltage based on its base voltage, enabling the signal conditioning module 30 to determine its output voltage based on the voltage divider. Specifically, VO3 = V1 - Vbe1, where VO3 is the output voltage of the signal conditioning module 30, and Vbe1 is the voltage between the base and emitter of transistor Q1, which can be, for example, 0.6V or 0.7V, depending on the selection of transistor Q1. Furthermore, the ratio of the voltage between the base and emitter of transistor Q2 (denoted as Vbe2) to the impedance of the impedance module 20 is the current supplied to the collector of transistor Q1, which is approximately equal to the current output from the emitter of transistor Q1 (i.e., the current output by the signal conditioning module 30), thus enabling the signal conditioning module 30 to determine its output current based on the impedance of the impedance module 20. Wherein, Vbe2 is, for example, 0.6V or 0.7V, which can be determined according to the selection of the second transistor Q2. When the impedance module 20 includes the second digital potentiometer DCP2, its impedance is the resistance between the first and second terminals of the second digital potentiometer DCP2 connected to the impedance module 20.

[0060] Based on the above embodiments, optionally, the first transistor Q1 is an NPN transistor and the second transistor Q2 is a PNP transistor.

[0061] Based on the above embodiments, optionally, the current amplification factor of both the first transistor Q1 and the second transistor Q2 is greater than 10^4, so that their base current is almost zero and the emitter current is basically equal to the collector current, thereby improving the voltage regulation accuracy.

[0062] Based on the above embodiments, optionally, when the voltage divider module 10 has a first digital potentiometer DCP1, the resistance value of the first digital potentiometer DCP1 can be set to be between 0.1 times and 1.25 times the resistance value of the first resistor R1. In other words, the resistance value of the first digital potentiometer DCP1 can be adjusted within the resistance range of 0.1 times and 1.25 times the resistance value of the first resistor R1. By setting 0.1*R1≤RD1≤1.25*R1, where RD1 is the resistance value of the first digital potentiometer DCP1 connected to the voltage divider module 10, it can be ensured that the voltage divided by the voltage divider module 10 is within the allowable range of the base voltage of the first transistor Q1, and that the first transistor Q1 operates in the linear region.

[0063] See also Figure 2 Based on the above embodiments, optionally, the output module 40 includes: a third resistor R3 and a fourth resistor R4; wherein, the third resistor R3 is connected between the output terminal of the electrical signal conditioning module 30 and the ground terminal of the adjustable voltage circuit; and the fourth resistor R4 is connected between the output terminal of the electrical signal conditioning module 30 and the voltage output terminal of the adjustable voltage circuit.

[0064] For the output module 40, both the third resistor R3 and the fourth resistor R4 are fixed-value resistors. The voltage difference between the output voltage of the electrical signal conditioning module 30 and the ground signal GND is the voltage across the third resistor R3. If the ground signal GND has a voltage of 0, then the output voltage of the electrical signal conditioning module 30 is the voltage across the third resistor R3. The current flowing through the third resistor R3 is obtained by dividing the voltage across the third resistor R3 by its resistance value. The current flowing through the fourth resistor R4 is obtained by subtracting the current output by the electrical signal conditioning module 30 from the current flowing through the third resistor R3. The voltage across the fourth resistor R4 is obtained by multiplying the current flowing through the fourth resistor R4 by its resistance value. The supply voltage VOUT is obtained by adding the voltage across the third resistor R3 and the voltage across the fourth resistor R4. The resistance values ​​of the third resistor R3 and the fourth resistor R4 can be selected according to actual needs; for example, their resistance values ​​can be set to be equal, such as 1kΩ each.

[0065] In summary, regarding Figure 2The adjustable voltage circuit in the circuit can be represented by the supply voltage VOUT as: VOUT=VO3+IO3*R4; where VO3=[RD1 / (R1+RD1)]*VCC-Vbe1, I03 is the current output by the electrical signal adjustment module 30, I03=[VO3 / R3-Vbe2 / RD2], and RD2 is the resistance value of the second digital potentiometer DCP2 connected to the impedance module 20. Therefore, when it is necessary to increase the supply voltage VOUT, RD1 can be increased and / or RD2 can be decreased; when it is necessary to decrease the supply voltage VOUT, RD1 can be decreased and / or RD2 can be increased.

[0066] Based on the above embodiments, optionally, the power supply voltage VCC can be set to a range of VCC≥7V, so that the adjustable range of the power supply voltage VOUT is larger, meeting the driving needs of more types of motors.

[0067] Based on the above embodiments, optionally, a large supply voltage VOUT may exceed the allowable voltage range of the sampling terminal of the control module 50. To solve this problem, in this embodiment of the invention, a sampling module can be added at the voltage output terminal to sample the supply voltage VOUT and proportionally reduce it to obtain the sampled supply voltage, so as to ensure that the sampled supply voltage corresponding to the supply voltage VOUT across the entire voltage range is within the allowable voltage range of the sampling terminal of the control module 50 and can be accurately identified by the control module 50. In this way, the requirements and selection limitations of the control module 50 can be reduced.

[0068] For details, see Figure 3 The adjustable voltage circuit also includes a sampling module 60 connected between the voltage output terminal and the ground terminal. The sampling module 60 samples the supply voltage VOUT and outputs a sampled supply voltage VREF from its output terminal. A control module 50 is connected to the output terminal of the sampling module 60. The control module 60 can indirectly obtain the value of the supply voltage VOUT by acquiring the sampled supply voltage VREF, which reflects the real-time status of the supply voltage VOUT. Specifically, the control module 50 can adjust the resistance value of at least one variable resistor based on the difference between the sampled supply voltage VREF and a preset sampling voltage. The preset sampling voltage is the sampled supply voltage corresponding to a preset voltage.

[0069] For example, the sampling module 60 can obtain the sampling supply voltage VREF through resistor voltage division. See details... Figure 4The sampling module 60 may include a fifth resistor R5 and a sixth resistor R6. The first end of the fifth resistor R5 is connected to the voltage output terminal. The second end of the fifth resistor R5 is connected to both the output terminal of the sampling module 60 and the first end of the sixth resistor R6. The output terminal of the sampling module 60 is connected to the control module 50. The second end of the sixth resistor R6 is connected to the ground terminal. The sampling module 60 obtains the sampling supply voltage VREF through the voltage divider between the fifth resistor R5 and the sixth resistor R6, and outputs it to the sampling terminal of the control module 50 via its output terminal. Both the fifth resistor R5 and the sixth resistor R6 are fixed-value resistors. For example, the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 can be determined based on the range of the supply voltage VOUT and the allowable voltage range of the sampling terminal of the control module 50, ensuring that the sampling supply voltage VREF corresponding to the supply voltage VOUT across the entire voltage range is within the allowable voltage range of the sampling terminal of the control module 50. For example, R6 = 10kΩ and R5 = 1MΩ.

[0070] For example, if the preset voltage is denoted as Ve, then the sampled preset voltage (denoted as Ver) is: Ver = (R6 / (R5+R6))*Ve. Let ΔV be the allowable output tolerance between the sampled supply voltage VREF and the sampled preset voltage. Then, when the difference between the sampled supply voltage VREF and the sampled preset voltage Ver is greater than the allowable output tolerance ΔV, the control module 50 controls the resistance value of at least one variable resistor in the adjustable voltage circuit until the difference between the sampled supply voltage VREF and the sampled preset voltage Ver is less than or equal to the allowable output tolerance ΔV, thus completing the voltage adjustment. It is understood that when the adjustable voltage circuit includes two variable resistors, during the voltage adjustment process, the control module 50 can switch the position and number of the adjustable variable resistors, as long as the adjusted supply voltage VOUT meets the requirements; the specific strategy is not limited here.

[0071] The voltage regulation process of this adjustable voltage circuit will be described below through a specific embodiment.

[0072] For example, adopting Figure 4 The circuit shown has a voltage divider module 10 with a variable resistor and an impedance module 20 with a second resistor R2 with a fixed value. The key parameters of each component in this circuit can be set as follows:

[0073] ① Resistors: R1 = 20kΩ, R3 = R4 = 1kΩ, R2 = R6 = 10kΩ, R5 = 1MΩ.

[0074] ② Digital resistor: RD1 = 10kΩ (the default value can be set to 10KΩ, and RD1 is adjustable during the adjustment process).

[0075] ③ NPN transistor: First transistor Q1, Vbe1=0.6V.

[0076] ④ PNP transistor: The second transistor Q2, Vbe2=0.6V.

[0077] ⑤ Power supply voltage VCC: +12V; Ground signal GND: 0V.

[0078] ⑥ Preset voltage Ve: 7V.

[0079] ⑦ Allowable output tolerance △V: 0.002V.

[0080] ⑧ The relationship between sampling supply voltage VREF and supply voltage VOUT: VREF=(R6 / (R5+R6))*VOUT.

[0081] Based on the above parameters, the power supply voltage VOUT output by the hardware circuit is 6.74V. The specific circuit calculations are as follows:

[0082] a. Connection methods for each component are as follows: Figure 4 Assuming that the two transistors are silicon (Si) with a base-emitter voltage of 0.6V, and that the current amplification factor (β value) of both transistors is very high (β>10^4), the base current is almost zero.

[0083] b. For the NPN transistor Q1, its base current is essentially zero. R1 and RD1 divide the +12V turn-on voltage to +4V. When Vbe1 is 0.6V, the emitter voltage of the transistor Q1, which is also the voltage output by the electrical signal conditioning module 30, is +3.4V, and the current flowing through the third resistor R3 is 3.4mA.

[0084] c. When the Vbe2 of the PNP type second transistor Q2 is 0.6V, the current in the second resistor R2 is 0.06mA (i.e., 60μA). With the base current of the second transistor Q2 almost zero, since the β value of the first transistor Q1 is very high, 60μA becomes the collector current of the first transistor Q1, and also becomes the emitter current of the first transistor Q1. That is, the current output by the electrical signal conditioning module 30 is 60μA.

[0085] d. The current flowing through the fourth resistor R4 is the difference between the 3.4mA current flowing through the third resistor R3 and the 0.06mA current flowing through the emitter of the first transistor Q1, which is 3.4 - 0.06 = 3.34mA. Based on this, the voltage drop across the fourth resistor R4 is 3.34V; and since the voltage applied to the top of the third resistor R3 is 3.4V, the supply voltage VOUT at this time is 6.74V.

[0086] Based on this, the circuit voltage regulation method is as follows:

[0087] The resistance value of the first digital potentiometer DCP1 is controlled by the software in the control module 50. After the digital resistor is set, the output terminal of the sampling module 60 is connected to the control module 50. The software in the control module 50 detects the value of the sampling supply voltage VREF and calculates whether it satisfies (R6 / (R5+R6))*Ve-△V≤VREF≤(R6 / (R5+R6))*Ve+△V.

[0088] If VREF < (R6 / (R5+R6))*Ve-△V, control module 50 controls the increase of RD1;

[0089] If VREF > (R6 / (R5+R6))*Ve+△V, control module 50 controls the reduction of RD1;

[0090] If the VREF voltage range satisfies ((R6 / (R5+R6))*Ve-△V, (R6 / (R5+R6))*Ve+△V), it indicates that the power supply voltage VOUT output meets the requirements of the preset voltage Ve, and the control module 50 does not adjust RD1.

[0091] It is understandable that ΔV can be set by itself in the program control logic of control module 50. The smaller ΔV is, the higher the output accuracy of the power supply voltage VOUT.

[0092] Using the above method, the adjustable voltage circuit can achieve programmable output of the power supply voltage VOUT by adjusting the resistance value RD1 in the voltage divider module 10 connected to the first digital potentiometer DCP1. The power supply voltage VOUT is: VOUT={[RD1 / (R1+RD1)]*VCC-Vbe1+[[[RD1 / (R1+RD1)]*VCC-Vbe1] / R3-Vbe2 / R2]*R4}.

[0093] In summary, the embodiments of the present invention provide an adjustable voltage circuit with a programmable voltage regulation function. After the preset voltage is set by programmable control, the difference between the current output power supply voltage VOUT and the preset voltage can be automatically checked, and the digital potentiometer parameters can be adjusted to regulate the output power supply voltage VOUT. After the output power supply voltage VOUT reaches the preset voltage requirement, the power supply voltage VOUT is maintained.

[0094] This invention also provides a control method for an adjustable voltage circuit, which, when applied to an adjustable voltage circuit provided in any embodiment of the invention, has corresponding beneficial effects. The control method for the adjustable voltage circuit is executed by a control module. The control method for the adjustable voltage circuit may include:

[0095] 1) Obtain the power supply voltage output from the voltage output terminal of the adjustable voltage circuit.

[0096] 2) When the difference between the supply voltage and the preset voltage does not meet the preset difference, adjust the resistance value of at least one variable resistor in the adjustable voltage circuit according to the relationship between the supply voltage and the preset voltage until the difference between the supply voltage and the preset voltage meets the preset difference.

[0097] The cases where the difference between the supply voltage and the preset voltage meets the preset difference include at least the case where the difference is equal to the preset difference, and may also include the case where the difference is less than the preset difference. The cases where the difference between the supply voltage and the preset voltage does not meet the preset difference include all cases other than those meeting the preset difference, such as the case where the difference is greater than the preset difference. For example, the preset difference is the upper limit of the allowable power supply error for the device to be powered, which can be determined according to actual needs.

[0098] It is understandable that if an adjustable voltage circuit includes multiple variable resistors, the resistance values ​​of some or all of the variable resistors can be adjusted during the adjustment process, and the selected variable resistor can also be changed during the adjustment process. The specific adjustment method is not limited here.

[0099] The control method for an adjustable voltage circuit provided in this invention, after determining the preset voltage to be output by the adjustable voltage circuit, controls the resistance value of at least one connected variable resistor based on the difference between the actual output supply voltage and the preset voltage. This adjusts the voltage division output of the voltage divider module and / or the impedance of the impedance adjustment module, thereby regulating the voltage and / or current output by the electrical signal adjustment module. This ensures that the difference between the supply voltage and the preset voltage meets the preset difference requirement, thus bringing the supply voltage closer to the preset voltage and realizing the voltage regulation function of the adjustable voltage circuit. In summary, the control method of this invention, applied to an adjustable voltage circuit with an adjustable supply voltage, allows the motor drive device containing the adjustable voltage circuit to drive more types of motors, improving the versatility of the motor drive device.

[0100] Figure 5 This is a flowchart illustrating a control method for an adjustable voltage circuit provided in an embodiment of the present invention. Optionally, in one specific implementation, see... Figure 5 The control method for this adjustable voltage circuit may include:

[0101] S110: Obtain the power supply voltage output from the voltage output terminal.

[0102] S120: Determine whether the difference between the power supply voltage and the preset voltage is greater than the preset difference; if yes, execute S130; if no, end the control.

[0103] When the adjustable voltage circuit does not have a sampling module, the control module can directly acquire the supply voltage and compare it with a preset voltage. When the adjustable voltage circuit has a sampling module, the control module can acquire the sampled supply voltage output by the sampling module and compare it with the sampled preset voltage (i.e., the sampled supply voltage corresponding to the preset voltage), and determine whether the difference between the sampled supply voltage and the sampled preset voltage is greater than the allowable output tolerance. The ratio of the allowable output tolerance to the preset difference is equal to the ratio of the sampled preset voltage to the preset voltage.

[0104] S130. Adjust the resistance value of at least one variable resistor according to the relationship between the power supply voltage and the preset voltage.

[0105] In this step, the direction of adjusting the variable resistor value is determined based on whether the supply voltage is greater than or less than the preset voltage, for example, by increasing or decreasing it, so that the adjusted supply voltage approaches the preset voltage. After this step is completed, the process can return to S110 to continue collecting the supply voltage and comparing it with the preset voltage until the difference between the supply voltage and the preset voltage is less than or equal to the preset difference, at which point the control ends and the voltage regulation is completed.

[0106] This embodiment implements the voltage regulation process based on S110-S130.

[0107] Specifically, targeting Figure 4 The control method steps for the circuit shown are as follows:

[0108] a. In the program logic, if VREF = (R6 / (R5+R6))*VOUT > (R6 / (R5+R6))*Ve + ΔV, then control to decrease RD1; if VREF = (R6 / (R5+R6))*VOUT < (R6 / (R5+R6))*Ve - ΔV, then control to increase RD1. In the specific circuit example above, the current sampling supply voltage VREF = 0.0667V, which is less than (R6 / (R5+R6))*Ve - ΔV = 0.0673V, therefore RD1 can be increased.

[0109] b. The control module outputs a digital control signal through IIC (serial communication protocol). The digital control signal may contain information related to the set value of the resistance RD1 of the first digital potentiometer DCP1 connected to the voltage divider module 10. The first digital potentiometer DCP1 receives the digital control signal and decodes it. Based on the set value, it determines the position of the selection contact and adjusts RD1.

[0110] c. The logic of a and b is repeatedly executed in the program, and finally (R6 / (R5+R6))*Ve-△V≤VREF≤(R6 / (R5+R6))*Ve+△V is achieved, so that the supply voltage VOUT tends to the preset voltage Ve.

[0111] This invention also provides a motor drive device, including an adjustable voltage circuit provided in any embodiment of the invention, which has corresponding beneficial effects. Figure 6 This is a schematic diagram of the structure of a motor drive device provided in an embodiment of the present invention. See also... Figure 6 The motor drive device may include a motor drive board 200 and an adjustable voltage circuit 100, with the motor drive board 200 connected to both the motor and the adjustable voltage circuit 100. The motor drive board 200 can control the amplitude of the motor speed signal supplied to the motor based on the supply voltage output from the adjustable voltage circuit 100. This motor can be used, for example, in electrical appliances such as air conditioners.

[0112] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0113] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An adjustable voltage circuit, characterized in that, include: A voltage divider module is connected between the power supply terminal and the ground terminal; the voltage divider module is used to divide the power supply voltage provided by the power supply terminal and output the divided voltage. An impedance module, wherein a first terminal of the impedance module is connected to the power supply terminal; wherein at least one of the voltage divider module and the impedance module includes a variable resistor, such that the voltage divider voltage and / or the impedance of the impedance module are adjustable; An electrical signal conditioning module is connected to the output terminal of the voltage divider module, the second terminal of the impedance module, the power supply terminal, and the voltage output terminal, respectively. The electrical signal conditioning module is used to determine the output voltage of the electrical signal conditioning module based on the voltage divider voltage, and to determine the output current of the electrical signal conditioning module based on the impedance of the impedance module. An output module is connected to the output terminal of the electrical signal conditioning module, the ground terminal, and the voltage output terminal, respectively; the output module is used to control the supply voltage output by the voltage output terminal according to the output voltage and current of the electrical signal conditioning module. A control module is connected to the voltage output terminal and each of the variable resistors; the control module is used to adjust the resistance value of at least one of the variable resistors according to the difference between the supply voltage and the preset voltage; The electrical signal conditioning module includes: The first transistor has its base connected to the output terminal of the voltage divider module, its collector connected to the second terminal of the impedance module, and its emitter connected to the output module. The base of the second transistor is connected to the collector of the first transistor, the emitter of the second transistor is connected to the power supply terminal, and the collector of the second transistor is connected to the voltage output terminal.

2. The adjustable voltage circuit according to claim 1, characterized in that, The voltage divider module includes: a first resistor and a first digital potentiometer; The first end of the first resistor is connected to the power supply terminal, the second end of the first resistor is connected to the first end of the first digital potentiometer and the electrical signal adjustment module, the second end of the first digital potentiometer is connected to the ground terminal, and the control terminal of the first digital potentiometer is connected to the control module; wherein, the first digital potentiometer serves as a variable resistor in the voltage divider module.

3. The adjustable voltage circuit according to claim 1 or 2, characterized in that, The impedance module includes: a second digital potentiometer, a first terminal of which is connected to the power supply terminal, a second terminal of which is connected to the electrical signal adjustment module, and a control terminal of which is connected to the control module; the second digital potentiometer serves as a variable resistor in the impedance module. or, The impedance module includes a second resistor, which is connected between the power supply terminal and the electrical signal conditioning module.

4. The adjustable voltage circuit according to claim 2, characterized in that, The resistance value of the first digital potentiometer is between 0.1 and 1.25 times the resistance value of the first resistor.

5. The adjustable voltage circuit according to claim 1, characterized in that, The output module includes: The third resistor is connected between the output terminal of the electrical signal conditioning module and the ground terminal; The fourth resistor is connected between the output terminal of the electrical signal conditioning module and the voltage output terminal.

6. The adjustable voltage circuit according to claim 5, characterized in that, The first transistor is an NPN transistor, and the second transistor is a PNP transistor; And / or, The current amplification factor of both the first transistor and the second transistor is greater than 10^4.

7. The adjustable voltage circuit according to claim 1, characterized in that, Also includes: A sampling module is connected between the voltage output terminal and the ground terminal; the sampling module is used to sample the supply voltage and output the sampled supply voltage. The control module is connected to the output terminal of the sampling module. The control module is used to adjust the resistance value of at least one of the variable resistors according to the difference between the sampling power supply voltage and the sampling preset voltage; wherein, the sampling preset voltage is equal to the sampling power supply voltage corresponding to the preset voltage.

8. The adjustable voltage circuit according to claim 7, characterized in that, The sampling module includes a fifth resistor and a sixth resistor; the first end of the fifth resistor is connected to the voltage output terminal, the second end of the fifth resistor is connected to the control module and the first end of the sixth resistor respectively, and the second end of the sixth resistor is connected to the ground terminal.

9. A control method for an adjustable voltage circuit, characterized in that, The adjustable voltage circuit, applied according to any one of claims 1-8, is executed by a control module; the control method for the adjustable voltage circuit includes: Obtain the supply voltage output from the voltage output terminal of the adjustable voltage circuit; When the difference between the supply voltage and the preset voltage does not meet the preset difference, the resistance value of at least one variable resistor in the adjustable voltage circuit is adjusted according to the relationship between the supply voltage and the preset voltage until the difference between the supply voltage and the preset voltage meets the preset difference.

10. A motor drive device, characterized in that, include: The motor drive board and the adjustable voltage circuit according to any one of claims 1-8, wherein the motor drive board is connected to the motor and the adjustable voltage circuit respectively.

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