Brushless motor rotating speed and current detection device

Abstract

The utility model discloses a brushless motor rotating speed and current detection device. The device comprises a device housing, a single-chip microcomputer, a current and voltage detection circuit, an interface, a rotating speed detection circuit and a power supply. The single-chip microcomputer, the interface, the current and voltage detection circuit, the rotating speed detection circuit and the power supply are all arranged in the device shell, the current and voltage detection circuit is connected with the single-chip microcomputer and used for detecting current signals and voltage signals of the brushless motor, the rotating speed detection circuit is connected with the single-chip microcomputer and used for detecting the rotating speed of the brushless motor, and the power supply is connected with the single-chip microcomputer. And the interface is used for being connected with a bus. According to the utility model, the actual operation rotating speed of the motor is calculated by detecting the ripple fluctuation of the input power supply bus, the device is small and exquisite in design and convenient to carry, the cost is greatly reduced, the device does not need to be connected to a final load end for testing, and the safety, portability and reliability of the testing process are ensured. The device meets various power supply modes, selects a USB-5V power supply, and provides great portability for users.

Description

Technical Field

[0001] The present application relates to the technical field of current detection, and in particular to a brushless motor speed and current detection device. Background Art

[0002] When testing a water pump, observing the motor speed can ensure that the equipment is running within a safe range and avoid possible dangers caused by excessive speed. At present, the main method for measuring motor speed is to use a traditional infrared tester, but the use of a traditional infrared tester is somewhat dangerous, and it is not suitable for water pumps that are generally submerged in water. Traditional electrical parameter speed meters also need to be connected to the phase line for testing. It is difficult to lead out the phase line of brushless motor products with built-in controllers, which makes testing inconvenient. Utility Model Content

[0003] The main purpose of this application is to provide a brushless motor speed and current detection device to solve the problem that the current traditional infrared tester has certain dangers and is not suitable for water pumps that are generally submerged in water. Traditional electrical parameter tachometers also need to be connected to the phase line for testing. The phase line of the brushless motor product with a built-in controller is difficult to lead out, and there are many inconveniences in testing.

[0004] In order to achieve the above-mentioned purpose, the present application provides the following technology: a brushless motor speed and current detection device, the device comprising a device housing, a single-chip microcomputer, a current and voltage detection circuit, an interface, a speed detection circuit and a power supply;

[0005] The single-chip microcomputer, interface, current and voltage detection circuit, rotation speed detection circuit and power supply are all arranged in the housing of the device. The current and voltage detection circuit is connected to the single-chip microcomputer and is used to detect the current signal and voltage signal of the brushless motor. The rotation speed detection circuit is connected to the single-chip microcomputer and is used to detect the rotation speed of the brushless motor. The power supply is connected to the single-chip microcomputer and is used to provide electrical energy to the device. The interface is used to connect the bus.

[0006] As an optional embodiment of the present utility model, optionally, the device further includes an operation button circuit, and the operation button circuit is connected to the single-chip microcomputer and is used to set the parameters of the brushless motor.

[0007] As an optional embodiment of the utility model, optionally, the operation button circuit includes an addition circuit, a subtraction circuit, a parameter selection circuit, a page turning circuit and a start circuit.

[0008] As an optional embodiment of the utility model, optionally, the subtraction circuit includes a resistor R96 and a key switch K33;

[0009] One end of the resistor R96 is connected to the power supply, the other end of the resistor R96 is connected to pin 1 of the key switch K33, pins 2 and 4 of the key switch K33 are connected to the single-chip microcomputer, and pin 3 of the key switch K33 is grounded;

[0010] The adding circuit includes a resistor R97 and a key switch K34;

[0011] One end of the resistor R97 is connected to the power supply, the other end of the resistor R97 is connected to pin 1 of the key switch K34, pins 2 and 4 of the key switch K34 are connected to the single-chip microcomputer, and pin 3 of the key switch K34 is grounded;

[0012] The parameter selection circuit includes a resistor R98 and a key switch K35;

[0013] One end of the resistor R98 is connected to the power supply, the other end of the resistor R98 is connected to pin 1 of the key switch K35, pins 2 and 4 of the key switch K35 are connected to the single-chip microcomputer, and pin 3 of the key switch K35 is grounded;

[0014] The page turning circuit includes a resistor R99 and a key switch K36;

[0015] One end of the resistor R99 is connected to the power supply, the other end of the resistor R99 is connected to pin 1 of the key switch K36, pins 2 and 4 of the key switch K36 are connected to the single-chip microcomputer, and pin 3 of the key switch K36 is grounded;

[0016] The startup circuit includes a resistor R100 and a key switch K37;

[0017] Among them, one end of the resistor R100 is connected to the power supply, the other end of the resistor R100 is connected to pin 1 of the key switch K37, pins 2 and 4 of the key switch K37 are connected to the microcontroller, and pin 3 of the key switch K37 is grounded.

[0018] As an optional embodiment of the present utility model, optionally, the device further includes a display screen, and the display screen is connected to the single-chip microcomputer and is used to display the parameters of the brushless motor.

[0019] As an optional embodiment of the utility model, optionally, the current and voltage detection circuit includes a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R17, a resistor R18, a resistor R16, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a comparator U5A, a comparator U6A, a comparator U5B and a transformer U7;

[0020] Among them, pin 3 of the transformer U7 is connected to the positive electrode of the power supply, pin 1 of the transformer U7 is grounded, pin 2 of the transformer U7 is connected to one end of the resistor R18, the other end of the resistor R18 is connected to pin 6 of the comparator U5B and one end of the resistor R17, the other end of the resistor R17 is connected to pin 7 of the comparator U5B, one end of the resistor R26, one end of the resistor R24 ​​and pin 3 of the comparator U6A, pin 4 of the comparator U5B is grounded, pin 8 of the comparator U5B is connected to the positive electrode of the power supply, the other end of the resistor R24 ​​is connected to one end of the capacitor C19 and one end of the resistor R23, the other end of the resistor R23 is connected to pin 2 of the comparator U6A and one end of the capacitor C18, the other end of the capacitor C18 is connected to the other end of the capacitor C19 and grounded, and pin 4 of the comparator U6A is grounded. Pin 1 of comparator U6A is connected to one end of resistor R19 and one end of resistor R21, the other end of resistor R19 is connected to a power supply, the other end of resistor R21 is connected to one end of capacitor C15 and pin 5 of comparator U5A, the other end of capacitor C15 is grounded, pin 8 of comparator U6A is connected to the power supply and one end of capacitor C17, the other end of capacitor C17 is connected to one end of resistor R22 and one end of capacitor C16, and grounded, the other end of resistor R22 is connected to pin 6 of comparator U5A, the other end of capacitor C16 and one end of resistor R25, the other end of resistor R25 is connected to the power supply and pin 8 of comparator U5A, pin 4 of comparator U5A is grounded, pin 7 of comparator U5A is connected to one end of resistor R20 and the microcontroller, and the other end of resistor R20 is connected to the positive pole of the power supply.

[0021] As an optional embodiment of the present utility model, optionally, the rotation speed detection circuit includes a rotation speed detection sensor U4 and a capacitor C14;

[0022] Among them, pin No. 4 of the speed detection sensor U4 is connected to the positive pole of the bus power supply, pin No. 5 of the speed detection sensor U4 is connected to the negative pole of the bus power supply, pin No. 3 of the speed detection sensor U4 is connected to the single-chip microcomputer, pin No. 2 of the speed detection sensor U4 is grounded, pin No. 1 of the speed detection sensor U4 is connected to one end of the capacitor C14 and the power supply, and the other end of the capacitor C14 is grounded.

[0023] As an optional embodiment of the utility model, optionally, the single chip microcomputer is also used to calculate the rotation speed of the brushless motor according to the current line number before filtering, the current signal after filtering and the pole pair number of the brushless motor.

[0024] Compared with the prior art, this application can bring the following technical effects: the utility model calculates the actual running speed of the motor by detecting the ripple fluctuation of the input power bus. The device is compact and easy to carry, which greatly reduces the cost and does not need to be connected to the final load end for testing, thus ensuring the safety, portability and reliability of the test process. The device meets multiple power supply modes, and can choose DC power supply, USB-5V power supply, and built-in button battery, providing users with great portability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0026] Figure 1 It is a structural schematic diagram of a brushless motor speed and current detection device of the utility model;

[0027] Figure 2 It is a structural schematic diagram of a brushless motor speed and current detection device of the utility model;

[0028] Figure 3 This is a schematic diagram of the current and voltage detection circuit structure of a brushless motor speed and current detection device of the utility model;

[0029] Figure 4 This is a schematic diagram of the speed detection circuit structure of a brushless motor speed and current detection device of the utility model;

[0030] Figure 5 The utility model is a schematic diagram of a key circuit structure of a brushless motor speed and current detection device.

[0031] In the figure: 1. device housing, 2. display screen, 3. buttons, 4. interface. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0035] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0036] In addition, the term "plurality" shall mean two or more.

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] In this embodiment, the operating parameters of each circuit can be configured by the user according to the actual motor detection conditions and requirements. The model and operating parameter value of each electronic component, such as resistance value, chip model, etc., are selected by the user. This embodiment does not limit the specific model.

[0039] like Figure 1 As shown, a brushless motor speed and current detection device, the device includes a device housing 1, a single chip microcomputer, a current and voltage detection circuit, an interface 4, a speed detection circuit and a power supply;

[0040] The single-chip microcomputer, interface 4, current and voltage detection circuit, speed detection circuit and power supply are all arranged in the device housing 1. The current and voltage detection circuit is connected to the single-chip microcomputer and is used to detect the current signal and voltage signal of the brushless motor. The speed detection circuit is connected to the single-chip microcomputer and is used to detect the speed of the brushless motor. The power supply is connected to the single-chip microcomputer and is used to provide electrical energy to the device. The interface 4 is used to connect the bus.

[0041] like Figure 2 As shown, when in use, the bus is connected to the interface 4, and the current and voltage detection circuit is used to detect the current signal and voltage signal of the bus. The detection device is connected to the brushless motor power bus through the interface 4, and a high-precision current sensor is connected internally. Then the signal is amplified by the operational amplifier, and the analog signal is converted into a speed cycle jump digital signal by the comparator, and input into the single-chip microcomputer for a series of digital signal processing algorithms, and the real-time speed is calculated and displayed on the liquid crystal display. At the same time, the voltage and current signals are also input into the single-chip microcomputer and displayed on the display through a series of filtering processes. By detecting the ripple fluctuation of the input power bus, the actual running speed of the motor is calculated. The device is compact in design, easy to carry, and the cost is greatly reduced. It does not need to be connected to the final load end for testing, which ensures the safety, portability and reliability of the test process. The device meets a variety of power supply methods, and can choose DC power supply, USB-5V power supply, and built-in button battery, which provides users with great portability. The model of the single-chip microcomputer is STM8S207R8T6.

[0042] As an optional embodiment of the utility model, optionally, the device further includes an operation button 3 circuit, and the operation button 3 circuit is connected to the single-chip microcomputer and is used to set the parameters of the brushless motor.

[0043] like Figure 1 As shown, the operation button 3 circuit can set the pole pair number of the brushless motor under test, the current and voltage reference, and adjust the backlight intensity of the LCD display.

[0044] As an optional embodiment of the present utility model, optionally, the operation button 3 circuit includes an addition circuit, a subtraction circuit, a parameter selection circuit, a page turning circuit and a start circuit.

[0045] like Figure 1 As shown, the brushless motor parameters can be adjusted according to actual conditions through the addition circuit, subtraction circuit, parameter selection circuit, page turning circuit and starting circuit.

[0046] like Figure 5 As shown, as an optional embodiment of the utility model, optionally, the subtraction circuit includes a resistor R96 and a key 3 switch K33;

[0047] One end of the resistor R96 is connected to the power supply, the other end of the resistor R96 is connected to the pin 1 of the key 3 switch K33, the pins 2 and 4 of the key 3 switch K33 are connected to the single-chip microcomputer, and the pin 3 of the key 3 switch K33 is grounded;

[0048] The adding circuit includes a resistor R97 and a key 3 switch K34; wherein one end of the resistor R97 is connected to a power supply, the other end of the resistor R97 is connected to pin 1 of the key 3 switch K34, pins 2 and 4 of the key 3 switch K34 are connected to a single-chip microcomputer, and pin 3 of the key 3 switch K34 is grounded;

[0049] The parameter selection circuit includes a resistor R98 and a key 3 switch K35; wherein one end of the resistor R98 is connected to a power supply, the other end of the resistor R98 is connected to pin 1 of the key 3 switch K35, pins 2 and 4 of the key 3 switch K35 are connected to a single-chip microcomputer, and pin 3 of the key 3 switch K35 is grounded;

[0050] The page turning circuit includes a resistor R99 and a key 3 switch K36; wherein one end of the resistor R99 is connected to a power source, the other end of the resistor R99 is connected to pin 1 of the key 3 switch K36, pins 2 and 4 of the key 3 switch K36 are connected to a single chip microcomputer, and pin 3 of the key 3 switch K36 is grounded;

[0051] The startup circuit includes a resistor R100 and a key 3 switch K37; wherein one end of the resistor R100 is connected to a power supply, the other end of the resistor R100 is connected to pin 1 of the key 3 switch K37, pins 2 and 4 of the key 3 switch K37 are connected to a single-chip microcomputer, and pin 3 of the key 3 switch K37 is grounded.

[0052] As an optional embodiment of the present utility model, optionally, the device further includes a display screen 2, and the display screen 2 is connected to the single-chip microcomputer and is used to display the parameters of the brushless motor.

[0053] like Figure 1 As shown, the display screen 2 is a liquid crystal display screen 2, which can display the brushless motor pole pair setting parameters, current and voltage reference parameters, and can display real-time speed, voltage, current and other parameters during the test.

[0054] As an optional embodiment of the utility model, optionally, the current and voltage detection circuit includes a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R17, a resistor R18, a resistor R16, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a comparator U5A, a comparator U6A, a comparator U5B and a transformer U7;

[0055] Transformer U7 preferably uses the dk106 sop-8 standard power supply chip.

[0056] Comparator U5A, comparator U6A, and comparator U5B can all use lf356n dip8 operational amplifier chip or Im324adr general operational amplifier chip.

[0057] For the connection of each chip, please refer to the drawings of this application.

[0058] Among them, pin 3 of the transformer U7 is connected to the positive electrode of the power supply, pin 1 of the transformer U7 is grounded, pin 2 of the transformer U7 is connected to one end of the resistor R18, the other end of the resistor R18 is connected to pin 6 of the comparator U5B and one end of the resistor R17, the other end of the resistor R17 is connected to pin 7 of the comparator U5B, one end of the resistor R26, one end of the resistor R24 ​​and pin 3 of the comparator U6A, pin 4 of the comparator U5B is grounded, pin 8 of the comparator U5B is connected to the positive electrode of the power supply, the other end of the resistor R24 ​​is connected to one end of the capacitor C19 and one end of the resistor R23, the other end of the resistor R23 is connected to pin 2 of the comparator U6A and one end of the capacitor C18, the other end of the capacitor C18 is connected to the other end of the capacitor C19 and grounded, and pin 4 of the comparator U6A is grounded. Pin 1 of comparator U6A is connected to one end of resistor R19 and one end of resistor R21, the other end of resistor R19 is connected to a power supply, the other end of resistor R21 is connected to one end of capacitor C15 and pin 5 of comparator U5A, the other end of capacitor C15 is grounded, pin 8 of comparator U6A is connected to the power supply and one end of capacitor C17, the other end of capacitor C17 is connected to one end of resistor R22 and one end of capacitor C16, and grounded, the other end of resistor R22 is connected to pin 6 of comparator U5A, the other end of capacitor C16 and one end of resistor R25, the other end of resistor R25 is connected to the power supply and pin 8 of comparator U5A, pin 4 of comparator U5A is grounded, pin 7 of comparator U5A is connected to one end of resistor R20 and the microcontroller, and the other end of resistor R20 is connected to the positive pole of the power supply.

[0059] like Figure 3As shown, the current and voltage detection circuit can detect the running status of the brushless motor in real time (including current signal, voltage signal, etc.), and the current signal and voltage signal are input to the microcontroller for further processing after a series of filtering processes.

[0060] As an optional embodiment of the present utility model, optionally, the rotation speed detection circuit includes a rotation speed detection sensor U4 and a capacitor C14;

[0061] Among them, pin No. 4 of the speed detection sensor U4 is connected to the positive pole of the bus power supply, pin No. 5 of the speed detection sensor U4 is connected to the negative pole of the bus power supply, pin No. 3 of the speed detection sensor U4 is connected to the single-chip microcomputer, pin No. 2 of the speed detection sensor U4 is grounded, pin No. 1 of the speed detection sensor U4 is connected to one end of the capacitor C14 and the power supply, and the other end of the capacitor C14 is grounded.

[0062] The rotation speed detection sensor U4 is preferably a CH701 current sensor IC chip.

[0063] As an optional embodiment of the utility model, optionally, the single chip microcomputer is also used to calculate the rotation speed of the brushless motor according to the current line number before filtering, the current signal after filtering and the pole pair number of the brushless motor.

[0064] like Figure 2 As shown, the single-chip microcomputer processes all the signals input from the operation button 3 and the current and voltage detection circuit and the speed detection circuit. The current signal is input into the single-chip microcomputer AD port after RC filtering, and the value after AD conversion is stored in RAM. The sliding average filtering method is used to calculate the filtered current value, and then the displayed current value is calculated by the conversion formula; the voltage signal sampling principle is the same as the current signal; the speed signal requires the current signal to be compared before and after filtering. The signal will output a flip signal with the same frequency as the motor commutation cycle through the second-order comparison circuit. The flip signal is input to the single-chip microcomputer timer capture input port, and the periodic frequency of the flip signal can be obtained. Combined with the number of motor pole pairs, the actual running speed of the motor can be calculated, and finally the LCD screen is driven to display the above parameters.

[0065] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A brushless motor speed and current detection device, characterized in that: The device comprises a device housing, a single chip microcomputer, a current and voltage detection circuit, an interface, a rotation speed detection circuit and a power supply; The single-chip microcomputer, interface, current and voltage detection circuit, rotation speed detection circuit and power supply are all arranged in the housing of the device. The current and voltage detection circuit is connected to the single-chip microcomputer and is used to detect the current signal and voltage signal of the brushless motor. The rotation speed detection circuit is connected to the single-chip microcomputer and is used to detect the rotation speed of the brushless motor. The power supply is connected to the single-chip microcomputer and is used to provide electrical energy to the device. The interface is used to connect the bus.

2. A brushless motor speed and current detection device as claimed in claim 1, characterized in that: The device also includes an operation button circuit, which is connected to the single-chip microcomputer and is used to set the parameters of the brushless motor.

3. A brushless motor speed and current detection device as claimed in claim 2, characterized in that: The operation button circuit includes an addition circuit, a subtraction circuit, a parameter selection circuit, a page turning circuit and a start circuit.

4. A brushless motor speed and current detection device as claimed in claim 3, characterized in that: The subtraction circuit includes a resistor R96 and a key switch K33; One end of the resistor R96 is connected to the power supply, the other end of the resistor R96 is connected to pin 1 of the key switch K33, pins 2 and 4 of the key switch K33 are connected to the single-chip microcomputer, and pin 3 of the key switch K33 is grounded; The adding circuit includes a resistor R97 and a key switch K34; One end of the resistor R97 is connected to the power supply, the other end of the resistor R97 is connected to pin 1 of the key switch K34, pins 2 and 4 of the key switch K34 are connected to the single-chip microcomputer, and pin 3 of the key switch K34 is grounded; The parameter selection circuit includes a resistor R98 and a key switch K35; One end of the resistor R98 is connected to the power supply, the other end of the resistor R98 is connected to pin 1 of the key switch K35, pins 2 and 4 of the key switch K35 are connected to the single-chip microcomputer, and pin 3 of the key switch K35 is grounded; The page turning circuit includes a resistor R99 and a key switch K36; One end of the resistor R99 is connected to the power supply, the other end of the resistor R99 is connected to pin 1 of the key switch K36, pins 2 and 4 of the key switch K36 are connected to the single-chip microcomputer, and pin 3 of the key switch K36 is grounded; The startup circuit includes a resistor R100 and a key switch K37; Among them, one end of the resistor R100 is connected to the power supply, the other end of the resistor R100 is connected to pin 1 of the key switch K37, pins 2 and 4 of the key switch K37 are connected to the microcontroller, and pin 3 of the key switch K37 is grounded.

5. A brushless motor speed and current detection device as claimed in claim 2, characterized in that: The device also includes a display screen, which is connected to the single-chip microcomputer and is used to display the parameters of the brushless motor.

6. A brushless motor speed and current detection device as claimed in claim 1, characterized in that: The current and voltage detection circuit includes a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R17, a resistor R18, a resistor R16, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a comparator U5A, a comparator U6A, a comparator U5B and a transformer U7; Among them, pin 3 of the transformer U7 is connected to the positive electrode of the power supply, pin 1 of the transformer U7 is grounded, pin 2 of the transformer U7 is connected to one end of the resistor R18, the other end of the resistor R18 is connected to pin 6 of the comparator U5B and one end of the resistor R17, the other end of the resistor R17 is connected to pin 7 of the comparator U5B, one end of the resistor R26, one end of the resistor R24 ​​and pin 3 of the comparator U6A, pin 4 of the comparator U5B is grounded, pin 8 of the comparator U5B is connected to the positive electrode of the power supply, the other end of the resistor R24 ​​is connected to one end of the capacitor C19 and one end of the resistor R23, the other end of the resistor R23 is connected to pin 2 of the comparator U6A and one end of the capacitor C18, the other end of the capacitor C18 is connected to the other end of the capacitor C19 and grounded, and pin 4 of the comparator U6A is grounded. Pin 1 of comparator U6A is connected to one end of resistor R19 and one end of resistor R21, the other end of resistor R19 is connected to a power supply, the other end of resistor R21 is connected to one end of capacitor C15 and pin 5 of comparator U5A, the other end of capacitor C15 is grounded, pin 8 of comparator U6A is connected to the power supply and one end of capacitor C17, the other end of capacitor C17 is connected to one end of resistor R22 and one end of capacitor C16, and grounded, the other end of resistor R22 is connected to pin 6 of comparator U5A, the other end of capacitor C16 and one end of resistor R25, the other end of resistor R25 is connected to the power supply and pin 8 of comparator U5A, pin 4 of comparator U5A is grounded, pin 7 of comparator U5A is connected to one end of resistor R20 and the microcontroller, and the other end of resistor R20 is connected to the positive pole of the power supply.

7. A brushless motor speed and current detection device as claimed in claim 1, characterized in that: The speed detection circuit includes a speed detection sensor U4 and a capacitor C14; Among them, pin No. 4 of the speed detection sensor U4 is connected to the positive pole of the bus power supply, pin No. 5 of the speed detection sensor U4 is connected to the negative pole of the bus power supply, pin No. 3 of the speed detection sensor U4 is connected to the single-chip microcomputer, pin No. 2 of the speed detection sensor U4 is grounded, pin No. 1 of the speed detection sensor U4 is connected to one end of the capacitor C14 and the power supply, and the other end of the capacitor C14 is grounded.

8. A brushless motor speed and current detection device as claimed in claim 1, characterized in that: The single chip microcomputer is also used to calculate the rotation speed of the brushless motor according to the current line number before filtering, the current signal after filtering and the number of pole pairs of the brushless motor.

Images