A DC motor drive device and control method

Abstract

The present invention discloses a DC motor driving device and a control method. The device includes an adjustable power supply unit, a boost unit, a driving voltage distribution unit, a MOS transistor driving unit, and an H-bridge unit. The output end of the adjustable power supply unit is respectively connected to the boost unit and the H-bridge unit. The output end of the boost unit is connected to the driving voltage distribution unit. The output end of the driving voltage distribution unit is connected to the MOS transistor driving unit. The output end of the MOS transistor driving unit is connected to the H-bridge unit. The present invention is used to improve the portability of the driving device, reduce the heat generation of the MOS transistor, and at the same time realize the function of independently and arbitrarily adjusting the speed of the wheels on both sides of the pipeline robot.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline robot control, and specifically to a DC motor drive device and a control method therefor. Background Art

[0002] Generally, a pipeline robot has two DC motors to drive the left and right wheels respectively to realize movements in all directions such as forward, backward, left turn and right turn. There are mainly two types of drive devices and control methods for the DC motors of existing pipeline robots: a combination of an adjustable DC power supply module and a relay to drive the motor, and a method of using a constant-voltage DC power supply module and an H-bridge to drive the motor.

[0003] For the combination of an adjustable DC power supply module and a relay to drive the motor, its drive device mainly includes a power supply unit and a relay drive unit. The power supply unit is an adjustable DC module, and the relay drive unit consists of three relays. The relay RL1 serves as a power switch to control whether to supply power to the two relays at the subsequent stage. The relays RL2 and RL3 respectively control the forward and reverse rotations of the motor, and the combination realizes the forward, backward, left and right movements of the robot.

[0004] The disadvantage of the combination of an adjustable DC power supply module and a relay to drive the motor is that the rotational speeds of the left and right wheels cannot be separately and arbitrarily controlled. From the structure of Technique One, it can be known that the voltages of the two motors of the robot are always equal and equal to the output voltage of the adjustable DC power supply module. Because the contacts of the relay are mechanical structures, the switching frequency is low, and the service life is also limited. High-frequency PWM control cannot be performed, and the working voltages of the two motors are always equal. Therefore, theoretically, the rotational speeds of the two motors are also equal. In scenarios where the driving direction of the robot needs to be fine-tuned in real time, the robot using this technique will need to perform operations such as frequent stopping - turning - moving forward, etc., which are cumbersome and inefficient.

[0005] For the method of using a constant-voltage DC power supply module and an H-bridge, it drives the motor through PWM (Pulse Width Modulation) technology. The drive device mainly includes a power supply unit and an H-bridge drive unit. The power supply unit is a constant-voltage DC power supply module, and the H-bridge drive unit mainly consists of 8 NMOS transistors and 4 MOS drive chips. 4 MOS transistors and 2 MOS drive chips form a group, and there are two groups of H-bridge circuits in total, with each group driving one motor respectively. By controlling the on and off times of the MOS transistors in each group through PWM signals, the average current flowing through the motor can be controlled, thereby realizing motor drive and control.

[0006] The disadvantages of the method of using a constant-voltage DC power supply module and an H-bridge are as follows:

[0007] 1) Poor portability. When a constant-voltage power supply module is used to supply power to the motor, the rated operating voltage of the motor also needs to be consistent with the output voltage of the power supply module, which has great limitations; when the motor is replaced, the power supply module also needs to be replaced together, resulting in poor portability.

[0008] 2) Large power loss and serious heating. When the MOS tube is always driven to turn on and off by PWM to control the motor, there will be switching losses and conduction losses on the MOS tube. Since the PWM frequency is relatively high, the switching loss of the MOS tube is much greater than the conduction loss, resulting in serious heating of the MOS tube and greatly affecting the service life of the driving device. Summary of the Invention

[0009] To overcome the deficiencies of the above-mentioned prior art, the present invention provides a DC motor driving device and a control method to improve the portability of the driving device, reduce the heating of the MOS tube, and simultaneously realize the function of independently and arbitrarily adjusting the speed of the wheels on both sides of the pipeline robot.

[0010] According to one aspect of the specification of the present invention, a DC motor driving device is provided, including an adjustable power supply unit, a boost unit, a driving voltage distribution unit, a MOS tube driving unit, and an H-bridge unit. The output end of the adjustable power supply unit is respectively connected to the boost unit and the H-bridge unit. The output end of the boost unit is connected to the driving voltage distribution unit. The output end of the driving voltage distribution unit is connected to the MOS tube driving unit. The output end of the MOS tube driving unit is connected to the H-bridge unit;

[0011] When performing PWM speed control of the motor, the adjustable power supply unit, the MOS tube driving unit, and the H-bridge unit are started. The MOS tube driving unit controls the conduction or cut-off of the MOS tubes in the H-bridge unit according to the control instruction to output the voltage and current output by the adjustable power supply unit to the motor to be speed-controlled within the conduction time of the MOS tubes;

[0012] When performing constant-voltage driving control of the motor, the adjustable power supply unit, the boost unit, the driving voltage distribution unit, the MOS tube driving unit, and the H-bridge unit are started. The boost unit superimposes the driving voltage on the voltage output by the adjustable power supply unit. The driving voltage distribution unit distributes the output voltage of the boost unit to the MOS tube driving unit. The MOS tube driving unit controls the MOS tubes in the H-bridge unit to be always on according to the control instruction to output the voltage and current output by the adjustable power supply unit to the motor in a constant-voltage manner.

[0013] When the above technical solution needs to perform PWM speed control of the motor, the output voltage and output current are adjusted in real time through the adjustable power supply unit. The MOS tube driving unit drives the MOS tubes connected to the motor in the H-bridge unit to conduct, realizing the independent control of any motor, and further realizing the function of independently adjusting the speed of the wheels on both sides of the pipeline robot.

[0014] When the above technical solution needs to perform constant voltage drive control on the motor, it controls the boost unit to generate a drive voltage, superimposes the drive voltage on the output voltage of the adjustable power supply unit, and through the distribution of the output voltage of the boost unit, combines with the MOS tube drive unit to drive the upper MOS tube of the H-bridge unit to conduct continuously, thereby achieving the purpose of constant voltage drive.

[0015] The above technical solution can perform PWM speed regulation control and constant voltage drive control on the motor without changing the hardware, and can switch freely between the two, thereby realizing different controls of the motor at a lower cost. The control method is flexible and the product cost is reduced.

[0016] As a further technical solution, the MOS tube drive unit includes 4 MOS tube drive chips, and the H-bridge unit includes 2 H-bridge branches; every 2 of the MOS tube drive chips are used to drive one H-bridge branch, and each H-bridge branch is used to connect one motor; each MOS tube drive chip is used to drive one arm of the H-bridge branch, and each arm is composed of two MOS tubes connected in series.

[0017] Furthermore, without changing the original hardware, by sending control instructions to the MOS tube drive unit, the on and off times of the MOS tubes on the corresponding H-bridge branch of the H-bridge unit are controlled, and then the energization time of the motor connected to this H-bridge branch is controlled. During this energization time, the speed and torque of the motor are adjusted by adjusting the output voltage and current of the adjustable power supply unit in real time, realizing the separate speed regulation control of the motor.

[0018] Furthermore, the on and off times of the 2 MOS tubes on any arm of the H-bridge branch can be separately controlled by the MOS tube drive chip, thereby realizing the separate control of the motor direction.

[0019] As a further technical solution, the MOS tube drive chip includes an input pin, an enable pin, and 2 output pins, where the input pin and the enable pin are used as input control terminals, and the 2 output pins are used as output control terminals.

[0020] Furthermore, different control instructions are received through the input control terminal, and different level signals are output from the output control terminal according to the control instructions, thereby controlling the conduction or cutoff of the MOS tubes in the H-bridge unit.

[0021] As a further technical solution, for any MOS tube drive chip, when the enable pin is at a low level, the two MOS tubes on the corresponding arm are cutoff; when the enable pin is at a high level and the input pin is at a high level, the upper MOS tube of the arm conducts and the lower MOS tube is cutoff; when the enable pin is at a high level and the input pin is at a low level, the upper MOS tube of the arm is cutoff and the lower MOS tube conducts.

[0022] Further, when the enable pin is at a low level, the two MOS transistors on the corresponding bridge arm are turned off, the motor stops driving, and the corresponding wheel of the pipeline robot brakes. When the enable pin is at a high level and the input pin is at a high level, the upper MOS transistor of the bridge arm conducts and the lower MOS transistor turns off, and the motor drives in reverse. The reverse time is related to the conduction time of the MOS transistor. The corresponding wheel of the pipeline robot steers. The longer the conduction time of the MOS transistor, the greater the steering amplitude of the wheel. When the enable pin is at a high level and the input pin is at a low level, the upper MOS transistor of the bridge arm turns off and the lower MOS transistor conducts, and the motor drives in reverse. At this time, the direction is opposite to the previous moment, and the corresponding wheel of the pipeline robot travels in the reverse direction.

[0023] As a further technical solution, the boost unit includes a charge pump boost circuit. This setting can further reduce the product cost and reduce the size.

[0024] As a further technical solution, the drive voltage distribution unit includes 4 optocoupler circuits, and each optocoupler circuit corresponds to driving the MOS transistor on one bridge arm. Signal isolation and voltage distribution are realized through the optocoupler circuit.

[0025] Further, by driving different optocoupler circuits to conduct, the output voltage superimposed with the drive voltage can be distributed to different MOS transistor driver chips, and then the MOS transistors on the corresponding bridge arms are driven to conduct and remain in the normally open state, realizing the constant voltage drive of the corresponding motor.

[0026] As a further technical solution, it further includes a control unit. The control unit is connected to the MOS transistor drive unit and is used to send motor PWM speed control instructions and motor constant voltage drive control instructions to the MOS transistor drive unit; it is connected to the boost unit and is used to start the boost unit; it is connected to the adjustable power supply unit and is used to adjust the output voltage and current in real time.

[0027] According to one aspect of the specification of the present invention, a control method for a DC motor drive device is provided, which is implemented by using the described device. The method includes:

[0028] After receiving the motor PWM speed control instruction, the MOS transistor drive unit controls the MOS transistors in the H-bridge unit to conduct according to the control instruction, and sends the voltage and current output by the adjustable power supply unit to the motor to be speed-regulated within the conduction time of the MOS transistors;

[0029] After receiving the motor constant voltage drive control instruction, the boost unit is controlled to start. The boost unit superimposes the drive voltage on the voltage output by the adjustable power supply unit. The drive voltage distribution unit distributes the output voltage of the boost unit to the MOS tube drive unit. The MOS tube drive unit controls the MOS tubes in the H-bridge unit to be normally open according to the control instruction, so as to output the voltage and current output by the adjustable power supply unit to the motor in a constant voltage manner.

[0030] When the above technical solution performs PWM speed regulation control, the MOS tube drive unit operates in the PWM drive mode, controls the on and off times of the MOS tubes on the H-bridge unit according to the input PWM signal, and within the on time, adjusts the rotational speed and torque of the corresponding motor by adjusting the output voltage and current of the adjustable power supply unit in real time, so as to realize the individual speed regulation control of the motor; when performing motor constant voltage drive control, the boost unit superimposes the drive voltage on the output voltage of the adjustable power supply unit, and distributes the superimposed output voltage to the MOS tube drive unit through the drive voltage distribution unit, driving the MOS tubes on the corresponding bridge arms of the H-bridge unit to conduct and remain normally open, realizing the motor constant voltage drive and improving the smoothness of the motor operation.

[0031] When the above technical solution does not require individual speed regulation control of the motor, it switches to the motor constant voltage drive mode, greatly reducing the heating risk of the drive device and improving the service life and stability of the equipment.

[0032] As a further technical solution, the MOS tube drive unit includes 4 MOS tube drive chips, and the H-bridge unit includes 2 H-bridge branches; every 2 MOS tube drive chips are used to drive one H-bridge branch, and each H-bridge branch is used to connect one motor; each MOS tube drive chip is used to drive one bridge arm of the H-bridge branch, and each bridge arm is composed of two MOS tubes connected in series.

[0033] As a further technical solution, the motor PWM speed regulation control instruction includes: setting the enable pins of the MOS tube drive chips corresponding to the motor to high level, and applying a PWM signal to the input pins; the motor constant voltage drive control instruction includes: setting the enable pins of the MOS tube drive chips corresponding to the motor to high level, and applying a constant high level or low level signal to the input pins according to the required running direction or stop state of the motor.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) When the motor PWM speed control is required in the present invention, the output voltage and output current are adjusted in real time by the adjustable power supply unit, and the MOS transistors connected to the motor in the H-bridge unit are driven to conduct by the MOS transistor driving unit, so as to realize the independent control of any motor, and further realize the independent speed regulation function of the wheels on both sides of the pipeline robot; when the constant voltage drive control of the motor is required, the boost unit is controlled to generate a drive voltage, and the drive voltage is superimposed on the output voltage of the adjustable power supply unit. By distributing the output voltage of the boost unit and combining with the MOS transistor driving unit, the upper MOS transistors of the H-bridge unit are driven to conduct continuously, so as to achieve the purpose of constant voltage drive.

[0036] (2) Without changing the hardware, the present invention can perform PWM speed control and constant voltage drive control on the motor, and can switch freely between the two, so as to realize different controls of the motor at a lower cost, with a flexible control method and reduced product cost.

[0037] (3) When the wheels on both sides of the pipeline robot do not need to be independently speed-regulated, the present invention can be switched to constant voltage drive at any time, which can greatly reduce the heat generation of the drive unit, improve the efficiency and stability, and reduce the power consumption.

[0038] (4) The present invention can drive motors of various specifications by replacing some components, and has a wide range of applicability. Description of the Drawings

[0039] Figure 1 FIG. is a schematic diagram of the principle of a DC motor drive device according to an embodiment of the present invention.

[0040] Figure 2 FIG. is a schematic diagram of the H-bridge branch and MOS transistor drive connected to the first motor according to an embodiment of the present invention.

[0041] Figure 3 FIG. is a schematic diagram of the H-bridge branch and MOS transistor drive connected to the second motor according to an embodiment of the present invention.

[0042] Figure 4 FIG. is a schematic diagram of the circuit of the boost unit according to an embodiment of the present invention.

[0043] FIG. 5(a)-(d) is a schematic diagram of the circuit of the drive voltage distribution unit according to an embodiment of the present invention. Detailed Embodiments

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0045] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "coupled" should be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0048] According to one aspect of the specification of the present invention, there is provided a DC motor driving device, as Figure 1 shown, comprising an adjustable power supply unit, a boost unit, a driving voltage distribution unit, a MOS transistor driving unit and an H-bridge unit. The output terminal of the adjustable power supply unit is respectively connected to the boost unit and the H-bridge unit. The output terminal of the boost unit is connected to the driving voltage distribution unit. The output terminal of the driving voltage distribution unit is connected to the MOS transistor driving unit. The output terminal of the MOS transistor driving unit is connected to the H-bridge unit.

[0049] The adjustable power supply unit mainly includes an adjustable power supply module, which can control the output voltage and output current according to requirements, and can correspondingly adjust the rotation speed and torque of the motor under normal conditions.

[0050] The H-bridge unit includes 8 MOS transistors, among which 4 MOS transistors form a group to connect and form an H-bridge branch, and each H-bridge branch is connected to a motor. By turning on and off the MOS transistors on the H-bridge branch, the steering, speed, and torque of the motor are controlled, and by adjusting the output voltage and current of the adjustable power supply unit within the conduction time of the MOS transistors, the individual speed control of the motor is achieved.

[0051] The MOS transistors in the H-bridge unit are all NMOS transistors.

[0052] The boost unit can be composed of a charge pump boost circuit, which superimposes the drive voltage on the output voltage of the adjustable power supply unit and supplies power to the MOS transistor drive unit when it is necessary to drive the upper-arm MOS transistors of the H-bridge for a long time.

[0053] The drive voltage distribution unit can be composed of an optocoupler circuit. Only when it is necessary to drive the upper-arm MOS transistors of the H-bridge, the output voltage of the boost unit is distributed to the MOS transistor drive unit. The drive voltage distribution unit can be mainly implemented by the optocoupler TLP127.

[0054] The MOS transistor drive unit drives the MOS transistors in the H-bridge unit to turn on and off according to the received control instructions. The MOS transistor drive unit can be mainly implemented by the IR2104 drive chip, and its drive voltage range is large and the drive voltage coverage is wide.

[0055] The drive voltage distribution unit and the MOS transistor drive unit automatically adapt to the externally input control instructions, and can drive the H-bridge unit to work in the normally open, normally closed, and PWM output states. It can not only perform individual PWM speed regulation on the motor to achieve individual control of the speeds of the wheels on both sides of the robot, but also, when the wheels on both sides of the pipeline robot do not require individual speed regulation, achieve constant voltage drive for the motor through the normally open MOS transistors in the H-bridge unit, improve the smooth operation of the motor, and can also greatly reduce the heat generation of the drive device and improve the service life and stability of the equipment.

[0056] As Figures 2-3 shown, the MOS transistor drive unit uses the MOS transistor drive chip IR2104. Two IR2104s form a group to drive the left and right two bridge arms in a single H-bridge branch respectively. One bridge arm is composed of 1 upper MOS transistor and 1 lower MOS transistor connected in series.

[0057] The functions of the MOS transistor drive chip IR2104 are mainly divided into two parts: ① Input control is achieved through the input pin IN and the enable pin SD; ② Output MOS transistor drive is achieved through the pins HO and LO.

[0058] When a low level is input to the enable pin SD, the MOS transistor drive chip IR2104 controls the pins HO and LO to output a low level, that is, turns off the upper and lower 2 MOS transistors.

[0059] When the enable pin SD inputs a high level and the input pin IN inputs a high level, the control pin HO of the MOSFET driver chip IR2104 is at a high level and the pin LO is at a low level, that is, the upper MOSFET is turned on and the lower MOSFET is turned off.

[0060] When the enable pin SD inputs a high level and the input pin IN inputs a low level, the control pin HO of the MOSFET driver chip IR2104 is at a low level and the pin LO is at a high level, that is, the upper MOSFET is turned off and the lower MOSFET is turned on.

[0061] For any motor of the wheels on both sides of the pipeline robot, by controlling the enable pin SD and the input pin IN of two MOSFET driver chips IR2104, the conduction of the four MOSFETs in the two arms of the H-bridge branch is realized in various combinations, so as to control the direction, braking, release, etc. of the motor.

[0062] As Figure 2 shown, when performing PWM speed regulation control on the first motor, both the MOSFET driver chip U2 and the MOSFET driver chip U6 only accept PWM drive.

[0063] For the MOSFET driver chip U2, when driving the upper MOSFET Q1, the driving voltage is supplied by the capacitor C1. When the MOSFET driver chip U2 controls the lower MOSFET Q3 to conduct, 12V Motor charges the capacitor C1 via the diode D1, charging the voltage across the capacitor C1 to 12V. When the MOSFET driver chip U2 controls the lower MOSFET Q3 to turn off, the potential of the capacitor C1 is raised, and the MOSFET driver chip U2 controls the HO to output a high level. At this time, a driving voltage of Vgs = 12V is provided to the upper MOSFET Q1, thereby controlling the upper MOSFET Q1 to conduct. Here, the capacitor C1 needs to be continuously charged, that is, the conduction of the upper MOSFET Q1 and the lower MOSFET Q3 needs to be continuously switched. Otherwise, if the upper MOSFET Q1 is continuously driven, the voltage across the capacitor C1 will continuously decrease until it is lower than the Vgs conduction threshold voltage of the MOSFET, resulting in the MOSFET not being able to continue to conduct as expected. Therefore, at this time, the MOSFET driver chip U2 can only accept PWM drive.

[0064] Similar to the MOSFET driver chip U2, when performing PWM speed regulation control on the first motor, the MOSFET driver chip U6 can also only accept PWM drive.

[0065] As Figure 3 shown, when performing PWM speed regulation control on the second motor, both the MOSFET driver chip U3 and the MOSFET driver chip U7 only accept PWM drive.

[0066] For the MOS transistor driver chip U3, when driving the upper MOS transistor Q2, the driving voltage is supplied by the capacitor C2. When the MOS transistor driver chip U3 controls the lower MOS transistor Q4 to conduct, 12V Motor charges the capacitor C2 via the diode D2, charging the voltage across the capacitor C2 to 12V. After the MOS transistor driver chip U3 controls the lower MOS transistor Q4 to turn off, the potential of the capacitor C2 is raised, and the MOS transistor driver chip U3 controls the HO to output a high level. At this time, a driving voltage of Vgs = 12V is provided to the upper MOS transistor Q2, thereby controlling the upper MOS transistor Q2 to conduct. Here, the capacitor C2 needs to be continuously charged, that is, the conduction of the upper MOS transistor Q2 and the lower MOS transistor Q4 needs to be continuously switched. Otherwise, if the upper MOS transistor Q2 is continuously driven, the voltage across the capacitor C2 will continuously decrease until it is lower than the Vgs conduction threshold voltage of the MOS transistor, resulting in the MOS transistor not being able to continue to conduct continuously as expected. Therefore, at this time, the MOS transistor driver chip U3 can only accept PWM drive.

[0067] Similar to the MOS transistor driver chip U3, when performing PWM speed control of the second motor, the MOS transistor driver chip U7 can also only accept PWM drive.

[0068] When it is necessary to switch this device to the working mode of driving the motor with constant voltage, start the boost unit to work, as Figure 4 shown, the control unit outputs a high-frequency PWM signal to the input pin of the boost circuit U9 through the VbDriver pin, controlling the boost unit to superimpose a 12V voltage on the motor supply voltage Vcc_Motor, so that the output voltage VbMotor of the boost unit is always 12V higher than Vcc_Motor.

[0069] For example, if it is necessary to achieve constant voltage drive for the first motor, that is, the motor connected to motor_out11 and motor_out12, then it is necessary to control the MOS transistors Q1 and Q7 to conduct continuously. If it is necessary to achieve constant voltage drive for the second motor, that is, the motor connected to motor_out21 and motor_out22, then it is necessary to control the MOS transistors Q2 and Q8 to conduct continuously.

[0070] When performing constant voltage drive control on the first motor, the control unit sets motor_in11, motor_sd11, and motor_sd12 to high level, and sets motor_in12 to low level. The high levels of motor_sd11 and motor_sd12 enable the MOS transistor driver chips U2 and U6, and the high level of motor_in11 drives the LO pin of the MOS transistor driver chip U2 to output a low level to control the MOS transistor Q3 to turn off, and drives the HO pin to output a high level to control the MOS transistor Q1 to conduct.

[0071] When motor_in11 is at high level, it will also control the optocoupler circuit U1 to conduct. As shown in Figure 5(a), VbMotor continuously supplies power to capacitor C1 through VB11 and maintains the voltage across its two ends at 12V, realizing the continuous conduction of the upper MOS transistor Q1. When motor_in12 is at low level, it will drive the pin HO of the MOS transistor driver chip U6 to output a low level to control the MOS transistor Q5 to turn off, and drive the pin LO to output a high level to control the lower MOS transistor Q7 to conduct, thus realizing the constant voltage drive of the first motor.

[0072] The voltage difference between the pin VB and the pin VS of the MOS transistor driver chip cannot be higher than 25V, otherwise it will cause damage to the MOS transistor driver chip.

[0073] In the constant voltage drive mode of the motor, when the pin VS of the MOS transistor driver chip U6 is 0V and motor_in12 is at low level, it cannot drive the optocoupler circuit U4 to conduct. As shown in Figure 5(b), that is, VbMotor is disconnected from VB12, then the voltage across capacitor C5 will not be charged above 12 + Vcc_Motor voltage, which can also protect the MOS transistor driver chip U6 from being damaged.

[0074] When performing constant voltage drive control on the second motor, the control unit sets motor_in21, motor_sd21, and motor_sd22 to high level, and sets motor_in22 to low. The high levels of motor_sd21 and motor_sd22 enable the MOS transistor driver chips U3 and U7. When motor_in21 is at high level, it drives the pin LO of the MOS transistor driver chip U3 to output a low level to control the MOS transistor Q4 to turn off, and drives the pin HO to output a high level to control the MOS transistor Q2 to conduct.

[0075] When motor_in21 is at high level, it will also control the optocoupler circuit U5 to conduct. As shown in Figure 5(c), VbMotor continuously supplies power to capacitor C2 through VB21 and maintains the voltage across its two ends at 12V, realizing the continuous conduction of the upper MOS transistor Q2. When motor_in22 is at low level, it will drive the pin HO of the MOS transistor driver chip U7 to output a low level to control the MOS transistor Q6 to turn off, and drive the pin LO to output a high level to control the lower MOS transistor Q8 to conduct, thus realizing the constant voltage drive of the second motor.

[0076] The voltage difference between the pin VB and the pin VS of the MOS transistor driver chip cannot be higher than 25V, otherwise it will cause damage to the MOS transistor driver chip.

[0077] In the constant voltage drive mode of the motor, the voltage of pin VS of the MOS transistor drive chip U7 is 0V, and motor_in22 is at a low level, which cannot drive the optocoupler circuit U8 to conduct. As shown in Figure 5(d), that is, VbMotor is disconnected from VB22, then the voltage across capacitor C6 will not be charged above 12 + Vcc_Motor voltage, and it can also protect the MOS transistor drive chip U7 from being damaged.

[0078] The present invention can realize the drive of motors of various specifications by replacing some components. This is because the parameters that different specifications of DC motors affect the circuit are mainly different voltages and currents, and the maximum voltage that the MOS transistor drive chip can drive can reach 625V. Although limited by the output voltage of the adjustable power supply unit, it can basically cover all DC motors with a working voltage lower than 60V. Therefore, only by adjusting the parameters such as the withstand voltage and current of the MOS transistors in the circuit, and the withstand voltage parameters of capacitors and diodes, etc., can it adapt to motors of various voltage and current specifications, and improve the portability of the drive device.

[0079] According to one aspect of the specification of the present invention, there is provided a control method for a DC motor drive device, which is implemented by using the described drive device. The method includes: after receiving a motor PWM speed regulation control instruction, the MOS transistor drive unit controls the MOS transistors in the H-bridge unit to conduct according to the control instruction, and sends the voltage and current output by the adjustable power supply unit into the motor to be speed-regulated during the conduction time of the MOS transistors; after receiving a motor constant voltage drive control instruction, the boost unit is controlled to start, and the boost unit superimposes the drive voltage on the voltage output by the adjustable power supply unit. The drive voltage distribution unit distributes the output voltage of the boost unit to the MOS transistor drive unit, and the MOS transistor drive unit controls the MOS transistors in the H-bridge unit to be normally open according to the control instruction, so as to output the voltage and current output by the adjustable power supply unit to the motor in a constant voltage manner.

[0080] The motor PWM speed regulation control instruction includes: setting the enable pins of the MOS transistor drive chips corresponding to the motor to high level, and applying a PWM signal on the input pins.

[0081] The motor constant voltage drive control instruction includes: setting the enable pins of the MOS transistor drive chips corresponding to the motor to high level, and applying a constant high level or low level signal on the input pins according to the required running direction or stop state of the motor.

[0082] When the above method performs PWM speed regulation control, the MOS tube driving unit operates in the PWM driving mode, controls the on and off time of the MOS tubes on the H-bridge unit according to the input PWM signal, and during the on time, adjusts the rotational speed and torque of the corresponding motor by adjusting the output voltage and current of the adjustable power supply unit in real time, so as to realize the independent speed regulation control of the motor; when performing the constant voltage driving control of the motor, the boost unit superimposes the driving voltage on the output voltage of the adjustable power supply unit, and distributes the superimposed output voltage to the MOS tube driving unit through the driving voltage distribution unit, drives the MOS tubes on the corresponding bridge arms of the H-bridge unit to conduct and remain in the normally open state, realizes the constant voltage driving of the motor, and improves the smoothness of the motor operation.

[0083] When the motor does not require independent speed regulation control, the above method switches to the constant voltage driving mode of the motor, greatly reducing the heating risk of the driving device and improving the service life and stability of the equipment.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A DC motor drive device, characterized in that, It includes an adjustable power supply unit, a boost unit, a drive voltage distribution unit, a MOS transistor drive unit, and an H-bridge unit. The output end of the adjustable power supply unit is respectively connected to the boost unit and the H-bridge unit. The output end of the boost unit is connected to the drive voltage distribution unit. The output end of the drive voltage distribution unit is connected to the MOS transistor drive unit. The output end of the MOS transistor drive unit is connected to the H-bridge unit. Among them, the MOS transistor drive unit includes 4 MOS transistor drive chips, and the H-bridge unit includes 2 H-bridge branches. Every 2 of the MOS transistor drive chips are used to drive one H-bridge branch, and each H-bridge branch is used to connect to one motor. Each of the MOS transistor drive chips is used to drive one arm of the H-bridge branch, and each arm is composed of two MOS transistors connected in series. When performing motor PWM speed regulation control, the adjustable power supply unit, the MOS transistor drive unit, and the H-bridge unit are started. The MOS transistor drive unit controls the conduction or cut-off of the MOS transistors in the H-bridge unit according to the control instruction, so as to output the voltage and current output by the adjustable power supply unit to the motor to be speed-regulated during the conduction time of the MOS transistors. When performing motor constant voltage drive control, the adjustable power supply unit, the boost unit, the drive voltage distribution unit, the MOS transistor drive unit, and the H-bridge unit are started. The boost unit superimposes the drive voltage on the voltage output by the adjustable power supply unit. The drive voltage distribution unit distributes the output voltage of the boost unit to the MOS transistor drive unit. The MOS transistor drive unit controls the MOS transistors in the H-bridge unit to be always on according to the control instruction, so as to output the voltage and current output by the adjustable power supply unit to the motor in a constant voltage manner.

2. The DC motor drive device according to claim 1, characterized in that, The MOS transistor drive chip includes an input pin, an enable pin, and 2 output pins. Among them, the input pin and the enable pin serve as input control ends, and the 2 output pins serve as output control ends.

3. The DC motor drive device according to claim 2, wherein, For any MOS transistor drive chip, when the enable pin is at a low level, the two MOS transistors on the corresponding arm are cut off. When the enable pin is at a high level and the input pin is at a high level, the upper MOS transistor of the arm conducts and the lower MOS transistor is cut off. When the enable pin is at a high level and the input pin is at a low level, the upper MOS transistor of the arm is cut off and the lower MOS transistor conducts.

4. The DC motor driving device according to claim 1, wherein, The boost unit includes a charge pump boost circuit.

5. The DC motor drive device according to claim 1, wherein, The drive voltage distribution unit includes 4 optocoupler circuits, and each optocoupler circuit corresponds to driving the MOS transistors on one arm.

6. The DC motor driving device according to claim 1, wherein It further includes a control unit. The control unit is connected to the MOS transistor drive unit and is used to send motor PWM speed regulation control instructions and motor constant voltage drive control instructions to the MOS transistor drive unit. It is connected to the boost unit and is used to start the boost unit. It is connected to the adjustable power supply unit and is used to adjust the output voltage and current in real time.

7. A control method for a DC motor drive device, implemented by using the device according to any one of claims 1-6, characterized in that, The method includes: After receiving the motor PWM speed regulation control instruction, the MOS transistor drive unit controls the MOS transistors in the H-bridge unit to conduct according to the control instruction, and sends the voltage and current output by the adjustable power supply unit to the motor to be speed-regulated during the conduction time of the MOS transistors. After receiving the motor constant-voltage drive control instruction, the boost unit is controlled to start. The boost unit superimposes the drive voltage on the voltage output by the adjustable power supply unit. The drive voltage distribution unit distributes the output voltage of the boost unit to the MOS transistor drive unit. The MOS transistor drive unit controls the MOS transistors in the H-bridge unit to be normally open according to the control instruction, so as to output the voltage and current output by the adjustable power supply unit to the motor in a constant-voltage manner. Among them, the MOS transistor drive unit includes 4 MOS transistor drive chips, and the H-bridge unit includes 2 H-bridge branches; every 2 of the MOS transistor drive chips are used to drive one H-bridge branch, and each H-bridge branch is used to connect one motor; each of the MOS transistor drive chips is used to drive one arm of the H-bridge branch, and each arm is composed of two MOS transistors connected in series.

8. The control method of a DC motor drive device according to claim 7, characterized in that, The motor PWM speed control instruction includes: setting the enable pins of the MOS transistor drive chips corresponding to the motor to high level and applying a PWM signal to the input pins; the motor constant-voltage drive control instruction includes: setting the enable pins of the MOS transistor drive chips corresponding to the motor to high level and applying a constant high-level or low-level signal to the input pins according to the required running direction or stop state of the motor.

Images