Integrated brushless motor control driver system based on non-inductive FOC

Abstract

The utility model provides an integrated brushless motor control driver system based on a non-inductive FOC, and the system comprises a main control center unit which is used for outputting a drive control signal after receiving a data sending command; the pre-driving module unit is used for receiving the driving control signal output by the main control center unit and processing and converting the driving control signal to obtain an analog driving signal for driving the brushless motor; the digital-analog coupling circuit is used for coupling a driving control signal output by the main control center unit with an analog driving signal of the pre-driving module unit through an integrated circuit (IC); the three-phase full-bridge inverter circuit is used for receiving the analog driving signal output by the pre-driving module unit and converting the analog driving signal from direct current into a three-phase alternating current signal; and the current sampling circuit is used for measuring current parameters in the operation state of the brushless motor. According to the invention, the integrated brushless motor control driver is realized, and the current sampling error is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of automation control, in particular to an integrated brushless motor control driver system based on sensorless FOC. Background Art

[0002] Brushless Direct Current Motor (BLDC) is an electric motor that does not require brushes and collector rings. Compared with the brushed DC motor (BDC) with brushes and collector rings integrated in the center of the armature, BLDC replaces the mechanical commutator with an electronic commutator. It has the advantages of low loss, simple maintenance, high conversion efficiency, excellent high-speed speed regulation performance, and high torque controllability. It is widely used in many fields such as robot joint control, industrial automation, aerospace, and medical equipment.

[0003] The BLDC control method mainly includes six-step commutation square wave drive and sine wave FOC (Field-Oriented Control) drive. The square wave drive controls the speed and torque of the brushless motor by adjusting the frequency and duty cycle, has good controllability, and the control method is simple. However, due to the sudden change of phase current and voltage harmonics, this drive method is prone to excessive motor rotation noise and high-frequency vibration out of control. Compared with the square wave drive method, the sine wave FOC drive uses the magnetic field orientation principle to control the excitation current and torque current of the motor respectively, so it has the advantages of low noise, low harmonics, high response speed, and high control accuracy. However, traditional brushless motor controllers and drivers often adopt a split design, the control signal is provided by an external controller, and the driver is integrated inside, so there are defects such as redundant electrical connections, large space occupation, and electromagnetic interference. Summary of the invention

[0004] In view of the problems existing in the prior art, an embodiment of the utility model provides an integrated brushless motor control driver system based on sensorless FOC.

[0005] The utility model provides an integrated brushless motor control driver system based on sensorless FOC, comprising:

[0006] The main control center unit is used to output a drive control signal after receiving a data transmission command;

[0007] A pre-drive module unit, wherein the input end of the pre-drive module unit is connected to the output end of the main control center unit, and the pre-drive module unit is used to receive the drive control signal output by the main control center unit, process and convert the drive control signal, and obtain an analog drive signal for driving the brushless motor;

[0008] A digital-analog coupling circuit, the digital-analog coupling circuit is connected to the main control center unit and to the pre-driver module unit, and the digital-analog coupling circuit is used to couple the drive control signal output by the main control center unit with the analog drive signal of the pre-driver module unit through an integrated IC;

[0009] A three-phase full-bridge inverter circuit, wherein the input end of the three-phase full-bridge inverter circuit is connected to the output end of the pre-driver module unit, and the three-phase full-bridge inverter circuit is used to receive the analog drive signal output by the pre-driver module unit, and use a MOSFET power device to convert the analog drive signal from direct current to a three-phase alternating current signal to adjust the voltage and frequency of the brushless motor;

[0010] A current sampling circuit is connected to the brushless motor, and is used to measure current parameters of the brushless motor in a running state.

[0011] According to an integrated brushless motor control driver system based on sensorless FOC provided by the utility model, the maximum bandwidth of the digital-to-analog coupling circuit is 440Mhz, the high-level logic input voltage range of the digital-to-analog coupling circuit is Vcc to Vcc-0.5V, the low-level logic input voltage range is 0V to 0.3V, and Vcc is a preset voltage.

[0012] According to an integrated brushless motor control driver system based on sensorless FOC provided by the utility model, the drive control signal output by the main control center unit is connected to the first pin of the coupling chip of the digital-to-analog coupling circuit, the analog drive signal output by the pre-drive module unit is connected to the second pin of the coupling chip, and the drive control signal and the analog drive signal are coupled and output through the third pin of the coupling chip.

[0013] According to an integrated brushless motor control driver system based on sensorless FOC provided by the utility model, the main control center unit is a 32-bit microcontroller, the main frequency of the microcontroller is up to 168Mhz, and the microcontroller includes a hardware floating-point unit FPU, 1MB of FLASH and 192KB of SRAM.

[0014] According to the utility model, an integrated brushless motor control driver system based on sensorless FOC is provided, which also includes a power module unit, and the power module unit is used to supply power to the main control center unit;

[0015] The power module unit includes a DCDC step-down circuit and a unidirectional Zener diode;

[0016] The DCDC step-down circuit is used to step down the input voltage of the power module unit;

[0017] The unidirectional Zener diode is used to protect the power module.

[0018] According to an integrated brushless motor control driver system based on sensorless FOC provided by the utility model, the pre-drive module unit includes:

[0019] A step-down charge pump, used to step down the voltage of the drive control signal;

[0020] The half-bridge circuit is used to amplify the current of the drive control signal through a three-phase full-bridge inverter circuit and a power tube.

[0021] According to an integrated brushless motor control driver system based on inductive FOC provided by the utility model, the drain-source voltage of the three-phase full-bridge inverter circuit is 60V, the drain current is 170A, the on-resistance is 2.3mΩ, and the gate short-circuit common-source input capacitance is 4248PF.

[0022] According to an integrated brushless motor control driver system based on sensorless FOC provided by the utility model, the three-phase full-bridge inverter circuit includes:

[0023] The driving signal of the upper half bridge and the driving signal of the lower half bridge pass through a single driving bridge arm composed of a gate resistor and a power tube and a single bridge arm composed of three driving signals;

[0024] The bus voltage passes through a power supply filter system composed of a single group of ceramic capacitors and a ground loop, and the power supply filter system is used to absorb the interference of high-frequency clutter components on the power supply.

[0025] According to an integrated brushless motor control driver system based on sensorless FOC provided by the utility model, the current sampling circuit includes three current sampling chips, and the current sampling chips are used to monitor the three-phase current of the brushless motor in the running state;

[0026] The pin of the current sampling chip enters the ADC acquisition pin of the main control center unit through a resistor, and the voltage flowing through the sampling resistor is calculated after being processed by the single-chip microcomputer.

[0027] According to the utility model, an integrated brushless motor control driver system based on sensorless FOC is provided, which also includes a brushless motor drive board. The power input and three-phase signal output ends of the brushless motor drive board are led out by a window-opening heat dissipation pad, and the board edge signal terminals of the brushless motor drive board are led out by a horizontal sticker with a lock, including a 2-pin CAN signal interface, a 4-pin Link download and burning interface, a 5-pin magnetic encoder inductive Hall interface, a 2-pin radial duct interface and a 4-pin axial IPS interface.

[0028] The utility model provides an integrated brushless motor control driver system based on sensorless FOC, which highly integrates the controller and the driver on a PCB through a digital-analog coupling circuit, and processes and collects signals through a main control center unit, a pre-drive module unit, a three-phase full-bridge inverter circuit and a current sampling circuit, thereby realizing an integrated brushless motor control driver, reducing system size and reducing current sampling errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 It is a structural schematic diagram of an integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0031] Figure 2 It is a schematic diagram of a control circuit of a digital-analog coupling unit in an integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0032] Figure 3 It is a schematic diagram of the control circuit of the main control center unit in the integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0033] Figure 4 It is a schematic diagram of a control circuit of a power module unit in an integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0034] Figure 5 This is a core circuit diagram of a pre-drive chip in an integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0035] Figure 6 It is a schematic diagram of a three-phase full-bridge inverter core circuit in an integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0036] Figure 7 It is a schematic diagram of a current sampling circuit in an integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0037] Figure 8 It is a schematic diagram of Clark transformation output waveform in the integrated brushless motor control driver system based on sensorless FOC provided by the utility model;

[0038] Fig. 9 It is a schematic diagram of the Park transformation output waveform in the integrated brushless motor control driver system based on the sensorless FOC provided by the utility model;

[0039] Fig.10 It is a schematic diagram of the output waveform of the sensorless FOC phase current of the brushless motor in the integrated brushless motor control driver system based on the sensorless FOC provided by the utility model;

[0040] Fig.11 It is a schematic diagram of the real-time output power of the motor in the integrated brushless motor control driver system based on the sensorless FOC provided by the utility model;

[0041] Fig.12 It is a schematic diagram of the motor response speed in the integrated brushless motor control driver system based on sensorless FOC provided by the utility model. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. 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.

[0043] Combine the following Figure 1 The utility model is described as an integrated brushless motor control driver system based on sensorless FOC, comprising:

[0044] The main control center unit is used to output a drive control signal after receiving a data transmission command;

[0045] A pre-drive module unit, wherein the input end of the pre-drive module unit is connected to the output end of the main control center unit, and the pre-drive module unit is used to receive the drive control signal output by the main control center unit, process and convert the drive control signal, and obtain an analog drive signal for driving the brushless motor;

[0046] A digital-analog coupling circuit, the digital-analog coupling circuit is connected to the main control center unit and to the pre-driver module unit, and the digital-analog coupling circuit is used to couple the drive control signal output by the main control center unit with the analog drive signal of the pre-driver module unit through an integrated IC;

[0047] A three-phase full-bridge inverter circuit, wherein the input end of the three-phase full-bridge inverter circuit is connected to the output end of the pre-driver module unit, and the three-phase full-bridge inverter circuit is used to receive the analog drive signal output by the pre-driver module unit, and use a MOSFET power device to convert the analog drive signal from direct current to a three-phase alternating current signal to adjust the voltage and frequency of the brushless motor;

[0048] A current sampling circuit is connected to the brushless motor, and is used to measure current parameters of the brushless motor in a running state.

[0049] like Figure 1 As shown, the system includes a main control center unit, a pre-drive module unit, a digital-analog coupling circuit, a three-phase full-bridge inverter circuit and a current sampling circuit.

[0050] Sensorless FOC control has the advantages of fast dynamic response, smooth motion torque, low noise, and high efficiency. However, when outputting sensorless square waves, there are problems such as pulsating torque, large noise and vibration, and poor low-speed starting performance. To address this problem, this paper proposes an integrated brushless motor control driver circuit system based on sensorless FOC. This system uses TI's high-current gate driver DRV8301 as the pre-drive core, optimizes the parameters of the power MOS tube, designs a digital-analog coupling circuit and a high-precision three-resistor high-end current sampling circuit, realizes the high integration of the controller and the driver, and reduces the current sampling error.

[0051] In terms of design, by designing a digital-analog coupling circuit, the controller and driver are integrated on a PCB (Printed Circuit Board), and the size can be only 5.5cmx5.5cm.

[0052] When selecting the pre-driver chip, a high-current gate driver DRV8301 can be used, paired with a power tube HYG025N06LS1C2 with a rated parameter of 60V 170A.

[0053] When selecting the current sampling chip, the high-precision, large-bandwidth AD8418WBRZ can be used.

[0054] After simulation test, this circuit system builds a sensorless FOC observation model, which can achieve low noise and stable torque output. After experimental test, this circuit system can output a stable FOC sine wave, the maximum peak output power can reach 720w, and the real-time current monitoring error does not exceed 1%. It has the advantages of small size, high burst, high-precision control, fast response speed, etc., and can be widely used in industrial automation control and other fields.

[0055] The processing flow of the brushless motor control driver system in this embodiment is mainly as follows: the user connects the external Link burner through the SW download circuit, and burns the pre-compiled code and firmware into the brushless motor controller system through the ST-Link Utility software. After the burning is completed, the user can communicate with the host computer software and the controller system through the serial port. After the indicator light status is normal, instructions can be sent and motor parameters can be adjusted in the UI interface of the host computer.

[0056] After receiving the data transmission command, the main control center unit is responsible for generating drive control signals. These drive signals include signals used to control the speed and direction of the brushless motor and other signals related to motor control, such as high-frequency PWM signals.

[0057] After receiving the drive control signal generated by the main control center unit, the pre-drive module unit processes and converts the drive control signal, including amplifying the transmitted signal through a three-phase high-power level through a MOSFET to provide an analog drive signal suitable for driving a brushless motor. At the same time, the brushless motor requires continuous switching of the three-phase sequence to work properly. The pre-drive module is responsible for implementing this commutation logic and determining when to switch the phase sequence based on the position and speed of the motor rotor.

[0058] After receiving the drive amplification signal from the pre-drive module unit power level, the three-phase full-bridge inverter circuit uses MOSFET power devices to convert DC power into a stable three-phase AC signal output, thereby adjusting the voltage and frequency. Secondly, the inverter circuit can accurately adjust the output AC voltage and frequency according to the drive control signal, thereby controlling the speed and torque of the driven brushless motor, and realizing precise control of the motor by continuously adjusting the on and off of the power switch device MOSFET in the inverter circuit.

[0059] The high-end current sampling circuit measures the current parameters of the motor in real time with higher accuracy and resolution through the high-end sampling circuit. After real-time monitoring of the current in the circuit, the current sampling circuit can provide a feedback signal to the main control center. After receiving the feedback signal, the main control center unit implements the underlying current loop closed-loop control that requires precise current control. This helps to dynamically adjust the current during system operation, improve robustness, and realize system energy management.

[0060] In summary, in the entire brushless motor control closed-loop system, the high-end current sampling circuit is responsible for real-time monitoring of the current value and transmitting the feedback signal to the main control center unit. The main control center unit receives the feedback signal and other inputs, calculates the control instruction and sends it to the pre-drive module unit and the three-phase full-bridge inverter circuit. The pre-drive module unit generates an appropriate drive signal based on the current feedback signal and the control instruction, controls the three-phase full-bridge inverter circuit, and thus realizes closed-loop control of the motor.

[0061] In this way, the entire brushless motor control closed-loop system can achieve precise current control, ensure stable operation of the brushless motor system, and make quick adjustments in the event of external interference or load changes, thereby improving the performance and reliability of the system.

[0062] like Figure 1 As shown, the system may also include a filter capacitor module, an LED (Light Emitting Diode) indicator light module, a crystal oscillator RCC (Reset and Clock Control) circuit, a SW (SoftWare) download circuit module, a reset RESET circuit module, a Vcp drive Typec analog serial port module, a CAN communication interface module, a DC-DC step-down module, a starting current-energy storage capacitor group module, an encoder interface, a radial IPS (In-Plane Switching) interface, an axial duct interface, a three-phase output interface and a power input interface.

[0063] For the filter capacitor module, when the brushless motor driver outputs current, the continuous opening and closing of the switching device MOSFET can easily cause rapid changes in current, thereby generating high-frequency noise and ripples, which can easily destroy the stability of the system and damage electronic components. The filter capacitor relies on its characteristic that the voltage will not suddenly change to smooth these current changes by storing and releasing charges, thereby reducing voltage ripple.

[0064] For the LED indicator module, in the brushless motor driver system, the LED indicator can display the working status of the system, such as the power-on status, the host computer connection status, and the running status. It can inform the user of the current working status by setting different flashing modes and different colors of LED indicator lights; it can also be used to indicate the fault status of the system, such as abnormal temperature failure, communication link failure, abnormal sensor failure, power failure, etc.

[0065] For the crystal oscillator RCC circuit module, in the brushless motor controller system, the crystal oscillator can generate accurate and stable clock signals, provide a reference pulse unit for the main control module, and synchronize the working rhythm of each module; at the same time, the PWM pulse width modulation signal output it carries can accurately control the speed and rotation direction of the brushless motor; the sensors in the system obtain the motor speed, position, angle and other information and also rely on stable clock signals to assist the controller in accurately processing sensor data and realizing closed-loop control of the controller and driver.

[0066] As for the SW download circuit module, it is used to download software programs (such as firmware, code, etc.) to the brushless motor drive controller system. This module communicates with a computer PC or other device through a serial port. The user can burn the compiled firmware into the system memory through this interface, and can also perform system debugging and testing, firmware updates, production burning, data transmission and formatting recovery functions.

[0067] The reset RESET circuit module is responsible for initializing the entire brushless motor controller system when the system is powered on or the reset button is pressed to ensure that it is in a reliable initial state; at the same time, when the controller is abnormal or fails, the reset module can restore the system to normal working state.

[0068] For the Vcp driver Typec analog serial port module, it is responsible for establishing virtual serial port communication between the brushless motor controller and the computer PC, so as to realize the debugging and configuration of the brushless motor controller in the host computer link. In the set UI interface, the user can send instructions to the controller, configure parameters, obtain data, observe and debug drive waveforms, etc.

[0069] For the CAN communication module, it is mainly responsible for realizing real-time communication between the brushless motor controller and other devices (such as PMSM motor, brushless motor, sensor), etc. Under the CAN bus, the communicating parties can transmit control commands to each other through the communication protocol, obtain sensor data and status information, etc. Due to its multi-node communication characteristics, even if multiple motors are under the same CAN bus, the stability and reliability of communication can be guaranteed.

[0070] For the starting current-energy storage current module, when the brushless motor starts at zero speed, a larger starting current is often required to overcome its own static friction and inertia. According to the starting requirements under different working conditions, adjusting the energy storage capacitor group of different capacities can adjust the size of the starting current to smooth the starting of the motor. At the same time, the large-capacity capacitor module can collect and store the external energy released when the motor decelerates or brakes. By reasonably deploying the capacitor module, the overall efficiency of the system can be improved, the starting process and energy recovery can be optimized, and the system performance can be improved.

[0071] The filter capacitor module, LED indicator module, crystal oscillator RCC circuit module, SW download circuit module, reset RESET circuit module, Vcp drive Typec analog serial port module and CAN communication module are all connected to the main control center unit STM32F405RGT6 according to their functions and interface characteristics.

[0072] The filter capacitor module is usually connected to the power pin of the main control center unit. The LED indicator module is usually connected to the GPIO pin of the main control center unit with the negative pole connected to GND. The state of the LED is controlled by setting the corresponding pin state. The crystal oscillator RCC circuit module is usually connected to the clock pin (such as HSE and LSE) of the main control center with a crystal oscillator drive circuit, and the system clock is provided by the crystal oscillator. The SW download circuit module is usually connected to the debug download interface of the main control center, such as the SWD interface. The reset RESET circuit module is usually connected to the reset pin (NRST) of the main control center. The Vcp drive Type-c analog serial port module is usually connected to the USB interface of the main control center, and its built-in USB function can realize analog serial port communication. The CAN communication module is usually connected to the CANH and CANL interfaces of the main control center. These interfaces are dedicated to the pins of CAN communication to realize communication between modules. Startup current-energy storage capacitor module: usually connected to the PWM output pin of the main control center to realize current control.

[0073] This embodiment highly integrates the controller and the driver on a PCB through a digital-analog coupling circuit, and processes and collects signals through a main control center unit, a pre-drive module unit, a three-phase full-bridge inverter circuit and a current sampling circuit, thereby realizing an integrated brushless motor control driver, reducing system size and reducing current sampling errors.

[0074] On the basis of the above embodiments, the maximum bandwidth of the digital-to-analog coupling circuit in this embodiment is 440Mhz, the high-level logic input voltage range of the digital-to-analog coupling circuit is Vcc to Vcc-0.5V, the low-level logic input voltage range is 0V to 0.3V, and Vcc is a preset voltage.

[0075] The digital-analog coupling unit design is mainly used to couple the digital signal of the main control center with the analog signal of the drive center through the integrated IC to achieve an integrated design.

[0076] In the selection of integrated chips, since the digital signal measurement parameters are represented by discrete signals, usually expressed as logical high and low levels, and the analog signal measurement parameters are represented by continuous signals, usually expressed as a continuously changing voltage range, and digital signals are usually transmitted at a fixed low-frequency transmission rate, the analog signals involve diverse frequency components, and signals working in different frequency ranges are prone to interfere with each other.

[0077] Therefore, considering the voltage parameter variation range and the operating frequency range, this design uses the MC74VHC1GT66 coupling chip with a wide input voltage range and high bandwidth. Its main performance parameters are: maximum 440Mhz bandwidth, high-level logic input voltage range: Vcc to Vcc-0.5V, low-level logic input voltage range: 0V to 0.3V.

[0078] On the basis of the above embodiments, in this embodiment, the drive control signal output by the main control center unit is connected to the first pin of the coupling chip of the digital-to-analog coupling circuit, the analog drive signal output by the pre-drive module unit is connected to the second pin of the coupling chip, and the drive control signal and the analog drive signal are coupled and output through the third pin of the coupling chip.

[0079] like Figure 2 As shown, in the design, the control digital signal that needs to be coupled is connected to pin 2 OUT / INYA, the driving analog signal is connected to pin 1 IN / OUTXA, the output signal CURR_FILTER is connected to the ON / OFFCTRL pin as the coupled signal, the system power supply 3.3V is connected to the VCC pin to ensure the power supply of the chip, and the system return ground pin absorbs the clutter and noise in the coupling process through a 100nF filter capacitor.

[0080] On the basis of the above embodiments, the main control center unit in this embodiment is a 32-bit microcontroller, the main frequency of the microcontroller is up to 168Mhz, and the microcontroller includes a hardware floating point unit FPU, 1MB FLASH and 192KB SRAM.

[0081] The main control center unit chip in this embodiment is selected as STM32F405RGT6, which is used to provide drive control signals. The main control chip is a 32-bit ARM Cortex-M4 core series microcontroller with a maximum main frequency of 168Mhz. At the same time, it has an internal integrated hardware floating point unit FPU, 1MB FLASH and 192KB SRAM. The designed main control center unit control circuit is as follows Figure 3 As shown, it can meet the storage of complex FOC algorithm programs and the use of integrated brushless motor control drivers.

[0082] On the basis of the above embodiment, this embodiment further includes a power module unit, and the power module unit is used to supply power to the main control center unit;

[0083] The power module unit includes a DCDC step-down circuit and a unidirectional Zener diode;

[0084] The DCDC step-down circuit is used to step down the input voltage of the power module unit;

[0085] The unidirectional Zener diode is used to protect the power module.

[0086] The power module unit is mainly used to power the main control unit of the brushless motor control driver. The module is designed with a low voltage drop concept. The main DCDC step-down circuit is as follows: Figure 4shown.

[0087] The power module unit SY8089A1AAC can be used with peripheral circuits to convert the 5V input voltage into a 3V3 output voltage, providing an output current of up to 2A, thereby meeting the requirements of minimum system circuit sleep current, working current, and continuous current of high-power wireless modules.

[0088] For the design of system protection circuits such as system output overcurrent protection circuit, input overvoltage protection circuit, and output overvoltage protection circuit, SMAJ5.0 unidirectional Zener diode is used, and its reverse withstand voltage is 5V. When the output voltage exceeds 5V, which is an abnormal value, the reverse Zener diode will enter a critical breakdown state and re-stabilize the output voltage at 5V, thereby protecting the circuit system.

[0089] On the basis of the above embodiment, the pre-driver module unit in this embodiment includes:

[0090] A step-down charge pump, used to step down the voltage of the drive control signal;

[0091] The half-bridge circuit is used to amplify the current of the drive control signal through a three-phase full-bridge inverter circuit and a power tube.

[0092] The pre-drive module unit mainly provides drive signals for brushless motor control, such as Figure 5 As shown. In the selection of the core pre-driver chip, since its Source and Gate (source and gate drive current) capabilities determine the maximum drive current provided to the power tube (MOSFET), the appropriate drive current can enable the motor to output sufficient torque and power, and the built-in fault detection and protection mechanism of the chip can effectively protect the safe and stable operation of the motor and the entire control system.

[0093] Therefore, considering the maximum drive current capability and functional integration, this design uses the DRV8301 pre-driver chip with large peak drive current output. Its main parameters are described as: supporting up to 1.7A source and 2.3A gate peak drive current, and the current detection error is less than ±0.5%.

[0094] In terms of design, RT_CLK, COM, VSENSE, BST_BK, and PH form an IC with a built-in DC-DC BUCK step-down charge pump, which converts the 24V input voltage into a 5V voltage output through TPS54160, providing 1.5A output current to power the 5V system. BST_A, GH_, SH_A and a 220nF bootstrap capacitor form a half-bridge circuit, which amplifies the current through a three-phase full-bridge inverter circuit with a power tube (MOSFET), thereby further driving the motor.

[0095] On the basis of the above embodiments, the drain-source voltage of the three-phase full-bridge inverter circuit described in this embodiment is 60V, the drain current is 170A, the on-resistance is 2.3mΩ, and the gate short-circuit common-source input capacitance is 4248PF.

[0096] The three-phase full-bridge inverter circuit is mainly used to convert DC signals into three-phase AC signals for driving motors. In the selection of N-channel power tubes (MOSFET), since its continuous drain current (Idss) determines the current that the output load brushless motor can carry, the size of the gate resistance determines the gate output current capacity. When the gate resistance is smaller, the output capacity is greater, and the internal parasitic capacitance is charged faster. Conversely, when the gate resistance is larger, the conduction time is longer and the switching speed is slower.

[0097] Therefore, considering the two factors of continuous drain current and gate resistance, this design adopts the HYG025N06LS1C2 power tube with large continuous drain current and small gate resistance. Its main performance parameters are: Vdss=60V, Idss=170A (25℃), Rdson=2.3mΩ, Ciss=4248PF.

[0098] On the basis of the above embodiment, the three-phase full-bridge inverter circuit in this embodiment includes:

[0099] The driving signal of the upper half bridge and the driving signal of the lower half bridge pass through a single driving bridge arm composed of a gate resistor and a power tube and a single bridge arm composed of three driving signals;

[0100] The bus voltage passes through a power supply filter system composed of a single group of ceramic capacitors and a ground loop, and the power supply filter system is used to absorb the interference of high-frequency clutter components on the power supply.

[0101] like Figure 6 As shown, in terms of design, the driving signal GH_A of the upper half bridge and the driving signal GL_A of the lower half bridge pass through the 4.7R gate resistor and the power tube to form a single set of driving bridge arms. The single set of bridge arms composed of three sets of driving signals together constitute a three-phase full-bridge inverter circuit; the bus voltage Vbus passes through a single set of 4.7uF ceramic capacitors (MLCC) and the ground loop to form a power filter system to absorb the interference of high-frequency clutter components on the total power supply of the system.

[0102] On the basis of the above embodiment, the current sampling circuit in this embodiment includes three current sampling chips, and the current sampling chips are used to monitor the three-phase current of the brushless motor in the running state;

[0103] The pin of the current sampling chip enters the ADC acquisition pin of the main control center unit through a resistor, and the voltage flowing through the sampling resistor is calculated after being processed by the single-chip microcomputer.

[0104] The high-end current sampling circuit is mainly used for collecting and monitoring the current parameters in the running state of the motor. Figure 7 As shown in the figure. In the selection of current sampling chip, since its accuracy and resolution directly affect the accuracy of current measurement, it determines the current parameter identification process of the underlying current loop PID algorithm. The larger the actual current of the measured circuit, the rated sampling current of the current sampling chip must be greater than the actual current of the measured circuit.

[0105] High-end sampling and low-end sampling are two different current measurement methods suitable for different application scenarios. High-end current sampling has the advantages of high precision, large bandwidth, low internal resistance and high resolution, while low-end current sampling is easily affected by the sampling resistor and introduces errors.

[0106] Therefore, considering the three factors of measurement accuracy, resolution and error reduction, this design uses the AD8418WBRZ high-end current sampling chip. Its main performance parameters are: 200V / V voltage gain, maximum ±12uA zero drift, and maximum gain measurement error of ±0.5%.

[0107] In terms of design, the three-phase line structure of the brushless motor with a phase difference of 120° determines that three current sampling chips AD8418WBRZ are needed to complete the monitoring of the three-phase current in the motor running state. In order to achieve a peak output power of 720W, under the premise of a bus input voltage of 24V, the actual current can reach up to 30A. Therefore, as shown in Formula 1, the sampling resistor is 1mΩ, P=5w, and the maximum monitoring current is calculated to be 70A. The reference voltage of 3.3v is provided by Vref as the reference level for high-end sampling to determine whether the voltage signal reaches the sampling threshold. At the same time, the 2.2uF ceramic capacitor couples the chip power supply voltage with the ground loop to filter out high-frequency clutter and reduce the error of current sampling. The OUT pin of the chip directly enters the ADC acquisition pin of the main control center through a resistor. After being processed by the microcontroller, the voltage flowing through the sampling resistor is calculated, thereby realizing the current measurement function.

[0108] P=I 2 ×R.

[0109] On the basis of the above embodiments, the present embodiment also includes a brushless motor drive board, the power input and three-phase signal output of the brushless motor drive board are led out by a window heat dissipation pad, and the board edge signal terminals of the brushless motor drive board are led out by a horizontal sticker with a lock, including a 2-pin CAN signal interface, a 4-pin Link download and burning interface, a 5-pin magnetic encoder inductive Hall interface, a 2-pin radial duct interface and a 4-pin axial IPS interface.

[0110] This system can use EDA professional software for PCB design. The following points should be followed in PCB design for brushless motor driver boards: (1) Ensure that the high-power drive signal return ground PGND and the digital signal ground GND are separated to reduce the interference of power echo on the signal. (2) The N-channel MOSFET of the power switch amplifier in the brushless motor driver board will generate a lot of heat, and a suitable heat dissipation solution needs to be designed to ensure stable operating temperature and long-term reliability. (3) Ensure that the digital signals mainly from the main control center unit and the analog signals of current and voltage monitoring are separated to prevent crosstalk between signals and affect signal quality. (4) Pay attention to the design of electromagnetic interference (EMI) and electromagnetic compatibility (EMC), including shielding the key signals of the circuit, avoiding long loops when wiring, and ensuring that the circuit operation will not be affected by external electromagnetic interference. (5) Optimize the drive current return path of the brushless motor, and use large-area copper plating and solder mask opening for the high-current load circuit to increase the copper foil's current resistance and heat dissipation capacity, and ensure sufficient current transmission performance and minimum voltage drop. (6) In terms of overall layout, the sub-modules are divided on the basis of keeping the volume as the priority as possible, reducing the loop area and ensuring 50Ω impedance matching. (7) The lamination sequence adopts a 4-layer board structure, which is effectively divided into the top layer, GND layer, power layer, and bottom layer. The GND and power signals are routed and coppered between specific layers to enhance anti-interference capabilities and reduce electromagnetic radiation interference.

[0111] After the design is completed, 3D simulation is performed to avoid related structural interference problems caused by welding and installation. The power input Vbus and the three-phase signal output are led out by a large-area heat dissipation pad with a window. The board edge signal terminal is led out by a horizontal GH1.25 (with a lock), including a 2-pin CAN signal interface, a 4-pin Link download and burn interface, a 5-pin magnetic encoder inductive Hall (HALL) interface, a 2-pin radial duct interface, and a 4-pin axial IPS interface.

[0112] In the simulation test, the model was built and the Simulink simulation analysis was carried out on the Matlab platform. The extended Kalman filter EKF observer was used to perform the Clark transformation in the FOC matrix transformation for the sensorless algorithm. Figure 8 As shown in the figure, the brushless three-phase AC phase current with a phase difference of 120°, namely the ia, ib and ic curves on the left side of the model, is used as the input of the Clark transformation model. After the model is built, the output is the iα and iβ curves on the right side of the model. The simulation framework results realize the conversion from three-phase AC current to two-phase AC current.

[0113] Perform Park transformation in FOC matrix transformation, such as Fig. 9As shown in the figure, the output iα and iβ (blue curve) of Clark transformation are used as the input of Park transformation model, and the excitation current Id and torque current Iq are output through model algorithm calculation. The simulation framework results realize the conversion from two-phase AC current to two-phase DC current.

[0114] In physical verification, after completing the PCB design, the GERBER file was exported and sent to the factory for board making. After the schematic diagram was exported to the BOM list for corresponding components purchase, the PCB board was immediately soldered after it arrived. At the same time, two large-capacitance topaz capacitors were connected to the input power supply to filter the input voltage and start slowly. The power input interface uses an XT60 female connector connected by 12Awg wire, and the three-phase output signal interface uses an MR30 male connector connected by 16Awg wire.

[0115] The test load object of this project is the 5065 brushless motor, which is a special hub motor for scooters and has no HALL line lead-out. The motor parameters are shown in Table 1.

[0116] Table 1 Motor parameters

[0117] Motor parameters Specific values Rated voltage U / V 24 Rated current I / A 75 <![CDATA[Rated power P n / W]]> 1800 Rated torque T / N·m 2 <![CDATA[Rated speed n / (rpm·min -1 )]]> 9600 Hall Angle H / ° 60 Magnetic flux F / mWb 0.68 Inductance L / μH 1.5 Resistance R / mΩ 20.7

[0118] The input power model is 6S 5500Mah TB47. When the system is powered on, the onboard 3.3V power indicator and 5V power indicator are both on, indicating that the circuit system power supply test is normal.

[0119] In the experimental test, a virtual oscilloscope is used to observe the physical test by connecting the circuit system to the main control center through the serial port. The initial test conditions are set as excitation current Id = 0, torque current Iq = 1, the open-loop driver is burned into the integrated brushless motor control driver, and the three-phase current output waveform of the oscilloscope is read as follows: Fig.10 shown.

[0120] The clamp meter is connected to the busbar of the actual circuit system to monitor the real-time output current of the motor in operation. At the same time, the excitation current Id=0 and the torque current Iq=4 are kept unchanged. The current loop closed-loop debugging of the dq axis is carried out and the full speed operation is maintained for 25 minutes. The real-time average current is read and two sets of data are recorded for data comparison and analysis, as shown in Table 2.

[0121] Table 2 Monitoring current and real-time current data

[0122]

[0123] Then, under the premise of input voltage of 24V, the motor is calibrated by using the sensorless algorithm. After the calibration is completed, the maximum output current under load conditions is verified based on the sensorless observed speed and rotor angle, and the motor is running at full speed of 8000rpm / min. The real-time peak output power of the motor is read. The curve is as follows: Fig.11 shown.

[0124] Finally, the speed loop is superimposed on the bottom current loop for dual-loop closed-loop feedback debugging. Under zero-speed starting, the motor response speed is tested. The dark curve represents the real-time speed climbing value, and the light curve represents the set speed value. The test results are as follows: Fig.12 shown.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. An integrated brushless motor control drive system based on sensorless FOC, It is characterized in that include: The main control center unit is used to output a drive control signal after receiving a data transmission command; A pre-drive module unit, wherein the input end of the pre-drive module unit is connected to the output end of the main control center unit, and the pre-drive module unit is used to receive the drive control signal output by the main control center unit, process and convert the drive control signal, and obtain an analog drive signal for driving the brushless motor; A digital-analog coupling circuit, the digital-analog coupling circuit is connected to the main control center unit and to the pre-driver module unit, and the digital-analog coupling circuit is used to couple the drive control signal output by the main control center unit with the analog drive signal of the pre-driver module unit through an integrated IC; A three-phase full-bridge inverter circuit, wherein the input end of the three-phase full-bridge inverter circuit is connected to the output end of the pre-driver module unit, and the three-phase full-bridge inverter circuit is used to receive the analog drive signal output by the pre-driver module unit, and use a MOSFET power device to convert the analog drive signal from direct current to a three-phase alternating current signal to adjust the voltage and frequency of the brushless motor; A current sampling circuit is connected to the brushless motor, and is used to measure current parameters of the brushless motor in a running state.

2. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The maximum bandwidth of the digital-to-analog coupling circuit is 440Mhz, the high-level logic input voltage range of the digital-to-analog coupling circuit is Vcc to Vcc-0.5V, the low-level logic input voltage range is 0V to 0.3V, and Vcc is a preset voltage.

3. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The drive control signal output by the main control center unit is connected to the first pin of the coupling chip of the digital-to-analog coupling circuit, the analog drive signal output by the pre-drive module unit is connected to the second pin of the coupling chip, and the drive control signal and the analog drive signal are coupled and output through the third pin of the coupling chip.

4. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The main control center unit is a 32-bit microcontroller, the main frequency of the microcontroller is up to 168Mhz, and the microcontroller includes a hardware floating point unit FPU, 1MB FLASH and 192KB SRAM.

5. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that It also includes a power module unit, which is used to supply power to the main control center unit; The power module unit includes a DCDC step-down circuit and a unidirectional Zener diode; The DCDC step-down circuit is used to step down the input voltage of the power module unit; The unidirectional Zener diode is used to protect the power module.

6. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The pre-driver module unit comprises: A step-down charge pump, used to step down the voltage of the drive control signal; The half-bridge circuit is used to amplify the current of the drive control signal through a three-phase full-bridge inverter circuit and a power tube.

7. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The drain-source voltage of the three-phase full-bridge inverter circuit is 60V, the drain current is 170A, the on-resistance is 2.3mΩ, and the gate short-circuit common-source input capacitance is 4248PF.

8. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The three-phase full-bridge inverter circuit comprises: The driving signal of the upper half bridge and the driving signal of the lower half bridge pass through a single driving bridge arm composed of a gate resistor and a power tube and a single bridge arm composed of three driving signals; The bus voltage passes through a power supply filter system composed of a single group of ceramic capacitors and a ground loop, and the power supply filter system is used to absorb the interference of high-frequency clutter components on the power supply.

9. The integrated brushless motor control driver system based on sensorless FOC according to claim 1, It is characterized in that The current sampling circuit includes three current sampling chips, and the current sampling chips are used to monitor the three-phase current of the brushless motor in operation; The pin of the current sampling chip enters the ADC acquisition pin of the main control center unit through a resistor, and the voltage flowing through the sampling resistor is calculated after being processed by the single-chip microcomputer.

10. The integrated brushless motor control driver system based on sensorless FOC according to any one of claims 1 to 9, It is characterized in that It also includes a brushless motor drive board, the power input and three-phase signal output of the brushless motor drive board are led out by a windowed heat dissipation pad, and the board edge signal terminals of the brushless motor drive board are led out by a horizontal sticker with a lock, including a 2-pin CAN signal interface, a 4-pin Link download and burning interface, a 5-pin magnetic encoder sensed Hall interface, a 2-pin radial duct interface and a 4-pin axial IPS interface.

Images