Hall filter circuit of brushless motor driver

Abstract

The utility model provides a brushless motor driver Hall filter circuit which comprises a first-stage filter circuit, a second-stage filter circuit and a third-stage filter circuit, the input end of the first-stage filter circuit is connected with a Hall signal, the output end of the first-stage filter circuit is connected with the input end of the second-stage filter circuit, and the output end of the third-stage filter circuit is connected with the output end of the third-stage filter circuit. The output end of the second-stage filter circuit is connected with the input end of the third-stage filter circuit, and the output end of the third-stage filter circuit is connected with the brushless motor driver logic conversion circuit. According to the utility model, the RC forms the first-stage filtering, the NPN triode forms the second-stage filtering, the three-stage filtering circuit formed by the NPN triode performs filtering commutation, the Hall filtering function of the direct-current brushless motor driver is realized through three-stage filtering, the burr interference is filtered, and the problem that the direct-current brushless motor driver cannot be damaged under the high-voltage working condition and the large-current working condition is solved. The problem that Hall signals are interfered to cause commutation errors of the motor is solved, the Hall signal filtering function of the direct-current brushless motor driver is achieved, and the anti-interference capability and reliability of the brushless motor driver are improved.

Description

Technical Field

[0001] The present application relates to the technical field of Hall filter motors, and in particular to a Hall filter circuit for a brushless motor driver. Background Art

[0002] With the rapid development of brushless DC motors in aerospace control system technology, high voltage, high current, and miniaturization of brushless DC motor drivers have become the main trends, placing higher and higher requirements on the signal processing capabilities of motor drivers. Because brushless DC motors are prone to high-frequency interference in Hall signals under high voltage and high current conditions, conventional logic processing circuits, software filtering algorithms, etc. can no longer effectively filter out burr interference. Under high voltage and high current conditions, Hall signals are interfered with, resulting in motor commutation errors. Traditional Hall filter circuits are composed of simple RC filters. Under high voltage and high current conditions, RC filtering alone can no longer effectively filter out interference glitches, resulting in commutation errors in brushless motor drivers and easy burning of power bridges. Utility Model Content

[0003] In order to solve the above problems, the present application proposes a brushless motor driver Hall filter circuit, which realizes the Hall level conversion function by performing three-level filtering on the Hall signal, realizes the Hall signal filtering function of the DC brushless motor driver, and improves the anti-interference ability and reliability of the brushless motor driver.

[0004] This application is implemented through the following technical solutions:

[0005] The present application proposes a brushless motor driver Hall filter circuit, comprising:

[0006] First-stage filter circuit;

[0007] Secondary filter circuit;

[0008] Three-stage filter circuit;

[0009] The input end of the first-stage filter circuit is connected to the Hall signal, the output end of the first-stage filter circuit is connected to the input end of the second-stage filter circuit, the output end of the second-stage filter circuit is connected to the input end of the third-stage filter circuit, and the output end of the third-stage filter circuit is connected to the brushless motor driver logic conversion circuit.

[0010] Furthermore, the first-stage filtering circuit includes a resistor R2 and a capacitor C1, one end of the resistor R2 is connected to the Hall signal, the other end of the resistor R2 is connected to one end of the capacitor C1, the end of the capacitor C1 away from the resistor R2 is grounded, and the node where the resistor R2 and the capacitor C1 are connected is connected to the second-stage filtering circuit.

[0011] Furthermore, the secondary filtering circuit includes a transistor Q1, a base of the transistor Q1 is connected to an end of the resistor R2 close to the capacitor C1, an emitter of the transistor Q1 is grounded, and a collector of the transistor Q1 is connected to the three-stage filtering circuit.

[0012] Furthermore, the three-stage filtering circuit includes a resistor R4, a capacitor C2 and a transistor Q2, one end of the resistor R4 is connected to the input voltage VCC, the other end of the resistor R4 is connected to the collector of the transistor Q1, one end of the capacitor C2 is connected to the collector of the transistor Q1, the other end of the capacitor C2 is grounded, the base of the transistor Q2 is connected to the collector of the transistor Q1, the emitter of the transistor Q2 is grounded, and the collector of the transistor Q2 is connected to the brushless motor driver logic conversion circuit.

[0013] Furthermore, the transistor Q1 and the transistor Q2 are both NPN transistors.

[0014] Furthermore, it includes a resistor R1 and a resistor R3, one end of the resistor R1 is connected to the input voltage VCC, the other end of the resistor R1 is connected to the end of the resistor R2 away from the capacitor C1, one end of the resistor R3 is connected to the base of the transistor Q1, and the other end of the resistor R3 is grounded.

[0015] The beneficial effects of the present application are as follows: the present invention realizes the Hall filter function of the brushless DC motor driver by using RC to form the first-stage filter, NPN transistor to form the second-stage filter, and then uses the three-stage filter circuit composed of NPN transistor to perform filtering and commutation. After the three-stage filter, the filtering characteristics of the transistor itself are used in combination with RC filtering to realize the Hall filter function of the brushless DC motor driver, and the burr interference is filtered out, which solves the problem of motor commutation error caused by interference with the Hall signal under high-voltage and high-current conditions, realizes the Hall signal filtering function of the brushless DC motor driver, and improves the anti-interference ability and reliability of the brushless motor driver. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. Obviously, the described embodiments are only a part of the embodiments of the utility model, not all of them. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0019] In addition, the descriptions of "first", "second", etc. in this application are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0020] Please refer to Figure 1 , the present application proposes a brushless motor driver Hall filter circuit, including a primary filter circuit, a secondary filter circuit and a tertiary filter circuit. The input end of the primary filter circuit is connected to the Hall signal, the output end of the primary filter circuit is connected to the input end of the secondary filter circuit, the output end of the secondary filter circuit is connected to the input end of the tertiary filter circuit, and the output end of the tertiary filter circuit is connected to the brushless motor driver logic conversion circuit. The Hall signal is filtered by the first-stage filter composed of RC and the second-stage filter composed of NPN transistors, and then the third-stage filter composed of NPN transistors is used for phase switching to filter out the burr interference of the Hall signal, which solves the problem of motor commutation errors caused by interference with the Hall signal under high-voltage and high-current conditions, thereby realizing the Hall signal filtering function of the DC brushless motor driver and improving the anti-interference ability and reliability of the brushless motor driver.

[0021] Specifically, the first-stage filter circuit includes a resistor R2 and a capacitor C1, one end of the resistor R2 is connected to the Hall signal HALL_IN, the other end of the resistor R2 is connected to one end of the capacitor C1, the end of the capacitor C1 away from the resistor R2 is grounded, and the node where the resistor R2 and the capacitor C1 are connected is connected to the second-stage filter circuit. The first-stage filter circuit is a primary filter circuit composed of RC, which performs the first-stage filtering on the Hall signal, can filter out most of the burrs, and obtain a relatively smooth Hall signal.

[0022] Further, after the first level filtering, the primary filter signal is passed into the secondary filter circuit for a second filtering process, specifically, the secondary filter circuit includes a transistor Q1, the base of the transistor Q1 is connected to one end of the resistor R2 close to the capacitor C1, the emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the three-level filter circuit. After the transistor Q1 receives the primary filter signal from the primary filter circuit, it performs a second filtering on the primary filter signal to obtain a secondary filter signal, which is smoother than the primary filter signal. Wherein, it also includes a resistor R1 and a resistor R3, one end of the resistor R1 is connected to the input voltage VCC, the other end of the resistor R1 is connected to one end of the resistor R2 far from the capacitor C1, one end of the resistor R3 is connected to the base of the transistor Q1, and the other end of the resistor R3 is grounded. The resistor R1, the resistor R2 and the resistor R3 provide bias current for the transistor Q1, so that the transistor Q1 can work in a suitable working range.

[0023] Furthermore, after the Hall signal is filtered by the primary filtering circuit and the secondary filtering circuit, a secondary filtering signal is obtained. Since the second filtering is through the transistor Q1, the polarity of the secondary filtering signal is reversed, and the secondary filtering signal needs to be filtered again and polarity converted by the three-stage filtering circuit. Specifically, the three-stage filtering circuit includes a resistor R4, a capacitor C2 and a transistor Q2, one end of the resistor R4 is connected to the input voltage VCC, the other end of the resistor R4 is connected to the collector of the transistor Q1, one end of the capacitor C2 is connected to the collector of the transistor Q1, the other end of the capacitor C2 is grounded, the base of the transistor Q2 is connected to the collector of the transistor Q1, the emitter of the transistor Q2 is grounded, and the collector of the transistor Q2 is connected to the logic conversion circuit of the brushless motor driver. The three-stage filtering circuit receives the two-stage filtering signal output from the two-stage filtering circuit, filters and converts the polarity of the two-stage filtering signal, and outputs the three-stage filtering signal, thereby obtaining a smoother output Hall signal HALL_OUT, which is then exported to the brushless motor driver logic conversion circuit so that the brushless motor driver logic conversion circuit can derive a smoother drive signal to drive the motor.

[0024] The working principle of the utility model is as follows: the input voltage VCC is used to power the motor Hall device, wherein VCC is generally 5V to 20V (typical value is 12V), HALL_IN is the Hall input signal, and HALL_OUT is the Hall filtered signal output. Resistors R1, R2 and R3 provide bias current for transistor Q1. Resistor R2 and capacitor C1 form an RC first-order low-pass filter. The Hall cutoff frequency can be set by formula f=1 / (2π·R2·C1). After the motor Hall signal passes through the RC first-order low-pass filter, it passes through the NPN transistor Q1. The slow response speed and minimum open pulse width characteristics of the transistor Q1 are used to filter out the burr interference in the Hall signal to achieve secondary filtering of the Hall signal. The collector of the NPN transistor Q1 outputs a signal. At this time, the polarity of the secondary filtering signal is opposite to that of the input Hall signal. Therefore, it passes through the transistor Q2 for polarity conversion. At the same time, the transistor Q2 is used for three filtering again to obtain the final Hall output signal HALL_OUT. The HALL_OUT signal can pass through the subsequent pull-up resistor to obtain the interference-free Hall signal required by the logic timing processing circuit.

[0025] Of course, the present application may have many other implementations. Based on the present implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present application.

Claims

1. A brushless motor driver Hall filter circuit, characterized in that: include: First-stage filter circuit; Secondary filter circuit; Three-stage filter circuit; The input end of the first-stage filter circuit is connected to the Hall signal, the output end of the first-stage filter circuit is connected to the input end of the second-stage filter circuit, the output end of the second-stage filter circuit is connected to the input end of the third-stage filter circuit, and the output end of the third-stage filter circuit is connected to the brushless motor driver logic conversion circuit.

2. The brushless motor driver Hall filter circuit according to claim 1, characterized in that: The primary filtering circuit includes a resistor R2 and a capacitor C1, one end of the resistor R2 is connected to the Hall signal, the other end of the resistor R2 is connected to one end of the capacitor C1, the end of the capacitor C1 away from the resistor R2 is grounded, and the node where the resistor R2 and the capacitor C1 are connected is connected to the secondary filtering circuit.

3. The brushless motor driver Hall filter circuit according to claim 2, characterized in that: The secondary filtering circuit includes a transistor Q1 , a base of the transistor Q1 is connected to an end of a resistor R2 close to a capacitor C1 , an emitter of the transistor Q1 is grounded, and a collector of the transistor Q1 is connected to the tertiary filtering circuit.

4. The brushless motor driver Hall filter circuit according to claim 3, characterized in that: The three-stage filtering circuit includes a resistor R4, a capacitor C2 and a transistor Q2, one end of the resistor R4 is connected to the input voltage VCC, the other end of the resistor R4 is connected to the collector of the transistor Q1, one end of the capacitor C2 is connected to the collector of the transistor Q1, the other end of the capacitor C2 is grounded, the base of the transistor Q2 is connected to the collector of the transistor Q1, the emitter of the transistor Q2 is grounded, and the collector of the transistor Q2 is connected to the brushless motor driver logic conversion circuit.

5. The brushless motor driver Hall filter circuit according to claim 4, characterized in that: The transistor Q1 and the transistor Q2 are both NPN transistors.

6. The brushless motor driver Hall filter circuit according to claim 4, characterized in that: It also includes a resistor R1 and a resistor R3, one end of the resistor R1 is connected to the input voltage VCC, the other end of the resistor R1 is connected to the end of the resistor R2 away from the capacitor C1, one end of the resistor R3 is connected to the base of the transistor Q1, and the other end of the resistor R3 is grounded.

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