An encoder acquires the angle of a servo drill driving circuit
The servo drill drive circuit, which combines an encoder and communication module with the FOC control algorithm, solves the shortcomings of sensorless and sensored drive schemes, realizes stable operation of the drill at low speeds and high-precision angle acquisition, and improves motor efficiency.
Patent Information
- Application Number
- CN202522769898.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-12-26
AI Technical Summary
In existing electric drill drive systems, sensorless drive solutions cannot acquire angle data at low speeds, leading to operational errors, while sensor-driven solutions have low angle acquisition accuracy, affecting motor efficiency.
The servo drill drive circuit uses an encoder to acquire angle information. The encoder is connected to the communication module, and the control module obtains the motor angle information. The FOC control algorithm is used to control the bridge of the drive module to turn on or off, ensuring that the motor runs normally at low speed and improving angle accuracy.
It enables normal operation of the motor at low speeds and high-precision angle acquisition, improves motor efficiency, and ensures stable operation of the electric drill at different speeds.
Smart Images
Figure CN224935595U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electric drill drive technology, specifically to a servo electric drill drive circuit that uses an encoder to collect angle data. Background Technology
[0002] An electric drill is a drilling tool powered by electricity. Its existing drive methods are divided into sensored and sensorless types. Sensorless drills calculate the motor angle by collecting back electromotive force (EMF), while sensored drills collect the angle using three switch halls. However, the sensorless drive scheme obtains the angle from the motor's back EMF and current. This method has certain requirements for motor speed; if the speed is too low, the angle cannot be collected, leading to operational errors. The sensored drive scheme relies on three switch halls for angle collection, resulting in low angle accuracy (only 60°), which can negatively impact motor efficiency. Utility Model Content
[0003] The technical problem to be solved by this utility model is to provide a servo electric drill drive circuit that uses an encoder to collect angles. This drive circuit will not have operational errors and has high motor efficiency.
[0004] To solve the above problems, the following technical solutions are provided: This utility model discloses a servo electric drill drive circuit for encoder-based angle acquisition, comprising a control module and a drive module. The input terminal of the drive module is connected to the power supply of the electric drill, and the output terminal is connected to the motor of the electric drill. The control module is adapted to the drive module, and the control unit is used to control the upper and lower bridges of the drive module to be on or off. Its key feature is that the drive module is adapted to a communication module, which is adapted to the encoder on the electric drill. The communication module transmits the angle information of the motor magnet relative to the encoder, acquired by the encoder, to the control module. The control module obtains the motor angle based on the angle information and controls the duty cycle of the upper and lower bridges of the drive module to be on or off based on the motor angle.
[0005] The communication module includes resistors R51 and R52. One end of resistor R51 and one end of resistor R52 are both connected to the control module, and the other ends of resistors R51 and R52 are both connected to the encoder. One end of resistor R51 connected to the control module is connected to one end of capacitor C30, and the other end of capacitor C30 is grounded. One end of resistor R52 connected to the control module is connected to one end of capacitor C31, and the other end of capacitor C31 is grounded. One end of resistor R51 connected to the encoder is connected to one end of resistor R49, and the other end of resistor R49 is connected to a 5V power supply. One end of resistor R52 connected to the encoder is connected to one end of resistor R50, and the other end of resistor R50 is connected to a 5V power supply.
[0006] The communication module includes a connector J7. Resistor R51 is connected to the encoder through pin 1 of connector J7, and resistor R52 is connected to the encoder through pin 2 of connector J7. Pin 3 of connector J7 is grounded and connected to the ground terminal of the encoder. Pin 4 of connector J7 is connected to a 5V power supply and is connected to one end of capacitor C28 and one end of capacitor C20, respectively. The other ends of capacitors C28 and C20 are both grounded.
[0007] The encoder contains a chip U2 with the model number MT6701CT-STD.
[0008] The power supply is a three-phase power supply, and the drive module is a three-phase drive bridge.
[0009] The three-phase drive bridge and control module are adapted to be connected to a current sampling circuit.
[0010] The control module contains a chip U1 with model number FU6866Q.
[0011] The above approach has the following advantages: Because the drive module of the servo drill drive circuit for encoder angle acquisition in this invention is adapted to connect to a communication module, and the communication module is adapted to connect to the encoder on the drill, the communication module transmits the angle information of the motor magnet relative to the encoder acquired by the encoder to the control module. The control module obtains the motor angle based on the angle information and controls the upper and lower bridges of the drive module to be turned on or off according to the motor angle. This solution uses encoder data as the basis for the motor angle, which is independent of the motor speed, thus ensuring that the motor can operate normally even at low speeds. Moreover, using encoder data as the basis for the motor angle provides higher angle accuracy and higher efficiency compared to the three-switch hall method in the prior art. Attached Figure Description
[0012] Figure 1 This is a structural topology diagram of the servo electric drill drive circuit for encoder angle acquisition according to this utility model; Figure 2 This is a circuit diagram of the control module in the servo electric drill drive circuit for encoder angle acquisition of this utility model. Figure 3 This is a circuit diagram of the communication module in the servo electric drill drive circuit for encoder angle acquisition of this utility model. Figure 4 This is a circuit diagram of the encoder in the servo electric drill drive circuit for encoder angle acquisition of this utility model. Figure 5 This is a circuit diagram of the drive module in the servo electric drill drive circuit for encoder angle acquisition of this utility model. Figure 6 This is a circuit diagram of the current acquisition circuit in the servo electric drill drive circuit for encoder angle acquisition according to this utility model. Detailed Implementation
[0013] The present invention will be further described in detail below with reference to the accompanying drawings.
[0014] like Figure 1 As shown, the servo electric drill drive circuit for encoder angle acquisition of this utility model includes an encoder, a control module, a drive module, and a communication module. The encoder is mounted on the electric drill; the specific mounting method is existing technology and will not be described in detail here. The encoder acquires the angle information of the motor's magnet relative to the encoder. The encoder is connected to the communication module, and the communication module is connected to the control module. The encoder sends the angle information to the control module through the communication module. The control module calculates the motor angle using the number of motor pole pairs and the angle offset between the motor and the encoder; the specific calculation process is existing technology and will not be described in detail here. The input terminal of the drive module is connected to the electric drill's power supply, and the output terminal of the drive module is connected to the electric drill's motor. Based on the motor angle, the control module controls the duty cycle of the upper and lower bridges of the drive module to be on or off using the FOC control algorithm, thereby achieving motor control. The FOC control algorithm is a conventional motor control algorithm and is existing technology, and will not be described in detail here.
[0015] In this embodiment, as Figure 2 As shown, the control module contains a chip U1 with model number FU6866Q, and peripheral circuitry for driving the operation of chip U1. The specific circuit structure is as follows. Figure 2 As shown, this is existing technology and will not be elaborated further here.
[0016] like Figure 3 and Figure 4 As shown, in this embodiment, the communication module includes resistors R51 and R52. The encoder contains a chip U2 of model MT6701CT-STD, and peripheral circuitry for driving the operation of chip U2. The specific circuit structure is as follows. Figure 4As shown. One end of resistor R51 and one end of resistor R52 are connected to the SCL and SDA pins of chip U1, respectively. The other ends of resistors R51 and R52 are connected to pins B and A of chip U2, respectively. One end of resistor R51 connected to chip U1 is connected to one end of capacitor C30, and the other end of capacitor C30 is grounded. One end of resistor R52 connected to chip U1 is connected to one end of capacitor C31, and the other end of capacitor C31 is grounded. One end of resistor R51 connected to chip U2 is connected to one end of resistor R49, and the other end of resistor R49 is connected to a 5V power supply. One end of resistor R52 connected to chip U2 is connected to one end of resistor R50, and the other end of resistor R50 is connected to a 5V power supply. The communication module contains connector J7. Resistor R51 is connected to the encoder through pin 1 of connector J7, and resistor R52 is connected to the encoder through pin 2 of connector J7. Pin 3 of connector J7 is grounded and connected to the ground terminal of the encoder. Pin 4 of connector J7 is connected to a 5V power supply and is connected to one end of capacitor C28 and one end of capacitor C20 respectively. The other ends of capacitors C28 and C20 are both grounded.
[0017] Specifically, in this embodiment, chip U1 communicates with chip U2 via I2C to obtain angle information. Pins 41 and 42 of chip U1 are the SDA and SCL pins for I2C communication, respectively. J7 is the wiring port, and resistors R49 and R50 are pull-up resistors, providing pull-up voltage for the SCL and SDA communication lines. R51 and R52 are used for current limiting to prevent sudden high voltage from damaging the chip. Pin 4 of J7 is connected to 5V to power the encoder, and pin 3 is grounded to allow chip U2 and chip U1 to share a common ground. Capacitors C28, C29, C30, and C31 are all used for filtering. Pins A and B of chip U2 are the I2C communication interface, connected to terminals 1 and 2 of J7 on the driver board. +5V and GND are also connected to terminals 4 and 3 of J7 on the board, respectively.
[0018] In this embodiment, the operating power supply is a three-phase power supply, and the drive module is a three-phase drive bridge. A current sampling circuit connects the three-phase drive bridge and the control module. Figure 5 This is a three-phase drive bridge for motor drive. Q2, Q3, Q4, Q6, Q7 and Q8 are MOS transistors that control the upper and lower bridge switches of each phase. HOU, HOV, HOW, LOU, LOV and LOW are the interfaces of chip U1 for controlling the MOS switches. Figure 6 This is a current acquisition circuit. IU, IV, and Ishunt respectively acquire the total three-phase current (U-phase and V-phase). AMP1P, AMP1M, AMP2P, AMP2M, AMP3P, and AMP3M are connected to the internal amplifier of chip U. The acquired current is used to control the three-phase current. The specific circuit structure is as follows: Figure 2 , Figure 5 andFigure 6 As shown, this is existing technology and will not be elaborated further here.
[0019] The control module and encoder of this utility model obtain the angle of the magnet on the motor relative to the encoder through I2C communication. Then, the motor angle is calculated by the number of motor pole pairs and the angle offset between the motor and the encoder. The calculated motor angle is then substituted into the FOC control algorithm to drive the motor through the three-phase drive bridge.
[0020] This solution uses an encoder to acquire angles for driving the electric drill load motor. The angle acquisition comes from the encoder chip, which has high angle accuracy, allowing for higher motor efficiency. The encoder can also acquire angles even when the motor is at low speed or not rotating, which is better for low-speed loads. The FOC control retains the inner current loop, which can control the phase current and control the torque.
Claims
1. A servo electric drill drive circuit for encoder-based angle acquisition, comprising a control module and a drive module; the input terminal of the drive module is connected to the power supply of the electric drill, the output terminal of the drive module is connected to the motor of the electric drill, the control module is adapted to the drive module, and the control unit is used to control the upper and lower bridges of the drive module to be turned on or off; characterized in that, The drive module is adapted to be connected to a communication module, which is adapted to be connected to the encoder on the electric drill. The communication module transmits the angle information of the motor magnet relative to the encoder, which is collected by the encoder, to the control module. The control module obtains the motor angle based on the angle information and controls the duty cycle of the upper and lower bridges of the drive module to be turned on or off based on the motor angle.
2. The servo drill drive circuit for encoder angle acquisition as described in claim 1, characterized in that, The communication module includes resistors R51 and R52. One end of resistor R51 and one end of resistor R52 are both connected to the control module, and the other ends of resistors R51 and R52 are both connected to the encoder. One end of resistor R51 connected to the control module is connected to one end of capacitor C30, and the other end of capacitor C30 is grounded. One end of resistor R52 connected to the control module is connected to one end of capacitor C31, and the other end of capacitor C31 is grounded. One end of resistor R51 connected to the encoder is connected to one end of resistor R49, and the other end of resistor R49 is connected to a 5V power supply. One end of resistor R52 connected to the encoder is connected to one end of resistor R50, and the other end of resistor R50 is connected to a 5V power supply.
3. The servo drill drive circuit for encoder angle acquisition as described in claim 2, characterized in that, The communication module includes a connector J7. Resistor R51 is connected to the encoder through pin 1 of connector J7, and resistor R52 is connected to the encoder through pin 2 of connector J7. Pin 3 of connector J7 is grounded and connected to the ground terminal of the encoder. Pin 4 of connector J7 is connected to a 5V power supply and is connected to one end of capacitor C28 and one end of capacitor C20, respectively. The other ends of capacitors C28 and C20 are both grounded.
4. The servo drill drive circuit for encoder angle acquisition as described in claim 1, characterized in that, The encoder contains a chip U2 with the model number MT6701CT-STD.
5. The servo drill drive circuit for encoder angle acquisition as described in claim 1, characterized in that, The power supply is a three-phase power supply, and the drive module is a three-phase drive bridge.
6. The servo drill drive circuit for encoder angle acquisition as described in claim 5, characterized in that, The three-phase drive bridge and control module are adapted to be connected to a current sampling circuit.
7. The servo drill drive circuit for encoder angle acquisition as described in claim 1, characterized in that, The control module contains a chip U1 with model number FU6866Q.