Motor back electromotive force energy absorption hardware circuit

Abstract

The utility model relates to the technical field of electronic circuit design, and discloses a motor counter electromotive force energy absorption hardware circuit, which comprises a resistor, a capacitor, a comparator, a grid electrode driving chip, an MOS tube and a power resistor, a power supply pin of the comparator is connected with 12V, a grounding pin of the comparator is connected with GND, a motor power supply signal VBUS is connected with a first end pin of an R3 resistor, and a second end pin of the R3 resistor is connected with a second end pin of the R3 resistor. The second end pin of the resistor R3 is connected with the negative electrode input of the comparator, the first end pin of the capacitor C1 and the first end pin of the resistor R4, the second end pin of the capacitor C1 is connected with the GND, and the second end pin of the resistor R4 is connected with the first end pin of the resistor R5. According to the motor counter electromotive force energy absorption hardware circuit, the motor counter electromotive force voltage absorption threshold value is started through hardware design, the power resistor is started to carry out energy absorption when the motor counter electromotive force is too high, and it is avoided that electronic components of a motor controller are broken down and damaged due to the too high motor counter electromotive force.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit design technology, specifically a hardware circuit for absorbing back EMF energy of a motor. Background Technology

[0002] A brushless DC (BLDC) motor is a type of electric motor that uses brushless motor technology. It is also known as a brushless DC motor or permanent magnet synchronous motor. Compared with traditional DC motors, BLDC motors do not require carbon brushes and commutators to achieve current commutation. Instead, they use an electronic commutator (also known as a controller) to control the direction and magnitude of the current. A BLDC motor consists of a permanent magnet and a stator. The permanent magnet is usually made of permanent magnet material and generates a constant magnetic field. There is a set of coils on the stator, called windings. By controlling the current in the windings, a rotating magnetic field can be generated. When the permanent magnet and the rotating magnetic field interact, torque is generated, which drives the motor to rotate.

[0003] Currently, existing brushless DC motors generate excessively high back EMF voltages when stopping at high speeds or in other ways, which can easily damage the three-phase inverter bridge drive circuit or cause breakdown of MOSFETs and TVS diodes. Therefore, there is an urgent need for a hardware circuit for absorbing back EMF energy in motors to solve the above problems. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this utility model provides a hardware circuit for absorbing back EMF energy in a motor. This circuit solves the problem that some brushless DC motors generate excessively high back EMF voltages when stopping at high speeds or in other ways, which can easily damage the three-phase inverter bridge drive circuit or cause breakdown of MOSFETs and TVS diodes.

[0006] (II) Technical Solution

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a hardware circuit for absorbing back EMF energy of a motor, including a resistor, a capacitor, a comparator, a gate driver chip, a MOSFET and a power resistor;

[0008] The comparator's power supply pin is connected to 12V, and its ground pin is connected to GND. The motor power supply signal VBUS is connected to the first pin of resistor R3. The second pin of resistor R3 is connected to the negative input of the comparator, the first pin of capacitor C1, and the first pin of resistor R4. The second pin of capacitor C1 is connected to GND. The second pin of resistor R4 is connected to the first pin of resistor R5. The second pin of resistor R5 is connected to GND. The 5V power supply is connected to the first pin of resistor R1. The second pin of resistor R1 is connected to the positive input of the comparator and the first pin of resistor R2. The second pin is connected to the output pin of the comparator and the negative input pin of the gate driver IC. The positive input pin of the gate driver IC is connected to 5V. The VDD pin of the gate driver IC is connected to the 12V power supply and the ground pin is connected to GND. The output pin of the gate driver is connected to the first pin of resistor R6. The second pin of resistor R6 is connected to the gate (G) of the MOSFET and the first pin of resistor R7. The second pin of resistor R7 is connected to GND. The drain (D) of the MOSFET is connected to the first pin of power resistor number 104. The source (S) of the MOSFET is connected to GND. The second pin of power resistor number 104 is connected to the motor power supply signal VBUS.

[0009] The beneficial effects of this utility model are:

[0010] The hardware circuit for absorbing back EMF energy of the motor is designed to activate the back EMF voltage absorption threshold. When the back EMF of the motor is too high, the power resistor is activated to absorb the energy, thus preventing the electronic components of the motor controller from being damaged due to excessive back EMF. Attached Figure Description

[0011] Figure 1 This is a block diagram of the circuit structure design of this utility model;

[0012] Figure 2 This is a schematic diagram of the driving signal transmission principle of this utility model;

[0013] Figure 3 This is a 3D view of the PCB design of this utility model. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] In the embodiments, by Figure 1-3This invention provides a hardware circuit for absorbing back EMF energy of a motor, comprising a resistor, a capacitor, a comparator, a gate driver chip, a MOSFET, and a power resistor.

[0016] The comparator's power supply pin is connected to 12V, and its ground pin is connected to GND. The motor power supply signal VBUS is connected to the first pin of resistor R3. The second pin of resistor R3 is connected to the negative input of the comparator, the first pin of capacitor C1, and the first pin of resistor R4. The second pin of capacitor C1 is connected to GND. The second pin of resistor R4 is connected to the first pin of resistor R5. The second pin of resistor R5 is connected to GND. The 5V power supply is connected to the first pin of resistor R1. The second pin of resistor R1 is connected to the positive input of the comparator and the first pin of resistor R2. The second pin is connected to the output pin of the comparator and the negative input pin of the gate driver IC. The positive input pin of the gate driver IC is connected to 5V. The VDD pin of the gate driver IC is connected to the 12V power supply and the ground pin is connected to GND. The output pin of the gate driver is connected to the first pin of resistor R6. The second pin of resistor R6 is connected to the gate (G) of the MOSFET and the first pin of resistor R7. The second pin of resistor R7 is connected to GND. The drain (D) of the MOSFET is connected to the first pin of power resistor number 104. The source (S) of the MOSFET is connected to GND. The second pin of power resistor number 104 is connected to the motor power supply signal VBUS.

[0017] It should be noted that the comparator model is TI LM393DR, the gate driver model is IC TI UCC27517DBVR, and the MOSFET model is Huayi Micro HYG015N10NS1 TA.

[0018] Specifically, refer to Figure 1 The motor back EMF voltage input is compared and output by the first-stage comparator signal, and then driven by the second-stage signal output of the gate driver chip to drive the logic level. The logic level controls the MOSFET to turn on or off, thereby opening or short-circuiting the power resistor. In this way, the power resistor forms a circuit to absorb the motor back EMF energy under short-circuit conditions.

[0019] Working principle:

[0020] When the back EMF voltage signal VBUS of the motor power supply, after being filtered and divided by capacitors R3, C1, R4, and R5 and resistors, is greater than the 5V power supply to the positive input of the comparator, the comparator outputs a logic low level. Resistor R2 provides hysteresis, ensuring the positive input voltage of the comparator is slightly lower than 5V to reduce fluctuations and trigger the inversion logic level. At this time, the comparator outputs a logic low level to the negative input pin of the gate driver IC. The gate driver IC operates on the principle of negative input-output inversion. When the negative input of the gate driver IC is low, the gate driver IC outputs a high level to the gate of the MOSFET. The MOSFET being sampled is an NMOS transistor. When the gate input is high, the drain and source terminals are turned on, and the circuit is activated. The power resistor can form a loop to absorb all the energy of the motor's back EMF. After the power resistor absorbs a certain amount of the motor's back EMF energy VBUS voltage, the voltage of VBUS after being filtered and divided by capacitors R3, C1, R4, and R5 and resistors will be continuously compared with the positive input hysteresis voltage of the comparator. Once it is lower than the positive input hysteresis voltage, the comparator output logic level is inverted and outputs a high level to the negative pin of the gate driver IC. When the negative pin of the gate driver IC is high, the gate driver IC outputs a low level to the G of the MOSFET. Since the NMOS is high, the D and S terminals are turned on. At this time, the D and S terminals of the MOSFET are in the open state, which disconnects the circuit of power resistor No. 104, forming an open circuit and preventing it from entering the working state.

[0021] When the voltage of the back EMF signal VBUS supplied by the motor is less than the 5V power supply at the positive input of the comparator after being filtered and divided by capacitors R3, C1, R4, and R5 and resistors, the comparator outputs a logic high level to the negative pin of the gate driver IC. When the negative pin of the gate driver IC is high, the gate driver IC outputs a low level to the gate of the MOSFET. Since the NMOS is high, the drain and source terminals are turned on. At this time, the drain and source terminals of the MOSFET are disconnected, which disconnects the circuit of power resistor No. 104, forming an open circuit and preventing it from entering the working state.

[0022] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hardware circuit for absorbing back EMF energy of a motor, characterized in that: This includes resistors, capacitors, comparators, gate driver chips, MOSFETs, and power resistors; The comparator's power supply pin is connected to 12V, and its ground pin is connected to GND. The motor power supply signal VBUS is connected to the first pin of resistor R3. The second pin of resistor R3 is connected to the negative input of the comparator, the first pin of capacitor C1, and the first pin of resistor R4. The second pin of capacitor C1 is connected to GND. The second pin of resistor R4 is connected to the first pin of resistor R5. The second pin of resistor R5 is connected to GND. The 5V power supply is connected to the first pin of resistor R1. The second pin of resistor R1 is connected to the positive input of the comparator and the first pin of resistor R2. The second pin is connected to the output pin of the comparator and the negative input pin of the gate driver IC. The positive input pin of the gate driver IC is connected to 5V. The VDD pin of the gate driver IC is connected to the 12V power supply and the ground pin is connected to GND. The output pin of the gate driver is connected to the first pin of resistor R6. The second pin of resistor R6 is connected to the gate (G) of the MOSFET and the first pin of resistor R7. The second pin of resistor R7 is connected to GND. The drain (D) of the MOSFET is connected to the first pin of power resistor number 104. The source (S) of the MOSFET is connected to GND. The second pin of power resistor number 104 is connected to the motor power supply signal VBUS.

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