阅读说明：本技术 一种直流电机负载在启动瞬间的控制方法 (Control method for DC motor load at starting moment ) 是由 陶国喜 周炳星 于 2020-06-17 设计创作，主要内容包括：本发明公开了一种直流电机负载在启动瞬间的控制方法,包括以下步骤：MCU单片机发出导通控制信号控制电机负载导通；硬件电路检测到电流过高,硬件电路切断电机负载供电并反馈过流信号给MCU单片机；MCU单片机读取到过流信号后断开导通控制信号,短暂延时后,在电机未停止转动时MCU单片机再次发出导通控制信号控制电机负载导通；直到电流值不再大于设定的最大电流值,硬件电路不再切断电机负载供电,电机开始正常转动；本发明利用直流电机的感性负载特性进行储能,采用软硬件配合的方式,MCU单片机软件程序多次周期性的快速推动电机转动,在负载功率超出一定值时断开电机负载,短暂延时后再次控制电机负载导通,如此循环数次,直至电机负载被完全推动。(The invention discloses a method for controlling the load of a direct current motor at the starting moment, which comprises the following steps: the MCU singlechip sends out a conduction control signal to control the conduction of the motor load; when the hardware circuit detects that the current is overhigh, the hardware circuit cuts off the power supply of a motor load and feeds an overcurrent signal back to the MCU singlechip; the MCU singlechip reads an overcurrent signal and then breaks off the conduction control signal, and after a short time delay, the MCU singlechip sends out the conduction control signal again to control the conduction of the motor load when the motor does not stop rotating; until the current value is no longer greater than the set maximum current value, the hardware circuit no longer cuts off the load power supply of the motor, and the motor starts to rotate normally; the invention utilizes the inductive load characteristic of the direct current motor to store energy, adopts a software and hardware matching mode, and the software program of the MCU singlechip periodically and rapidly pushes the motor to rotate for a plurality of times, disconnects the motor load when the load power exceeds a certain value, controls the motor load to be conducted again after short time delay, and the operation is repeated for a plurality of times until the motor load is completely pushed.)

1. A control method for a direct current motor load at the starting moment is characterized by comprising the following steps:

(1) the MCU singlechip sends out a conduction control signal to control the conduction of the load of the motor, the motor rotates, and the current is increased;

(2) when the hardware circuit detects that the current is overhigh, the hardware circuit cuts off the load power supply of the motor and feeds an overcurrent signal back to the MCU singlechip, and the motor keeps rotating due to inertia but the rotating speed is rapidly reduced;

(3) the MCU singlechip reads an overcurrent signal and then breaks off the conduction control signal, and after a short time delay, the MCU singlechip sends out the conduction control signal again to control the load of the motor to be conducted when the motor does not stop rotating, and the motor continues to rotate;

(4) and (4) repeating the steps (2) and (3) until the current value is no longer greater than the set maximum current value, the hardware circuit no longer cuts off the power supply of the motor load, the motor starts to normally rotate, and the motor is started.

2. The method for controlling the load of the direct current motor at the starting moment according to claim 1, wherein the MCU singlechip adopts STM32 series chips.

3. The method for controlling the load of the direct current motor at the starting moment according to claim 1 or 2, wherein a software control process of the MCU singlechip adopts a programming method of a state machine, an initialization state bit is 0, and the software control process specifically comprises the following steps:

(1) when the status flag bit is 0, the MCU singlechip sends out a conduction control signal to turn on a load motor, and simultaneously sets the status flag bit to 1 and starts timing;

(2) when the status flag bit is 1, judging whether the timing duration reaches the set duration, if not, continuing timing, otherwise, setting the status flag bit to be 2;

(3) when the status flag bit is 2, judging whether the read feedback signal shows overcurrent or not, if the feedback signal shows no overcurrent, indicating that the motor load works normally, so that the status flag bit and the starting times are initialized for circularly detecting the feedback signal next time; if the feedback signal shows overcurrent, judging whether the starting times are smaller than a set value, if the starting times are larger than the set value, closing the corresponding motor load, setting an overcurrent flag bit of the corresponding motor load, initializing a state flag bit and the starting times, and then not restarting the motor load; if the starting times are less than the set values, closing the corresponding motor load, adding 1 to the starting times, setting the state flag position to be 3 and starting timing;

(4) when the status flag bit is 3, judging whether the timing time length reaches the set time length, if not, continuing timing, otherwise, setting the status flag bit to be 0, and waiting for the next cycle to try to start the motor load again;

(5) when the software has an error, so that the status flag bit is not in the four states of 0, 1, 2 and 3, the status flag bit is reset to 0, and the next cycle of restarting the starting attempt is waited.

4. A method for controlling the load of a dc motor at the moment of starting according to claim 3, wherein the set time duration in steps (2) and (4) of the software control flow is 10 ms.

5. The method for controlling the load of the direct current motor at the starting moment according to claim 1, wherein the hardware circuit in the step (2) obtains an actual current value through a sampling resistor and compares the actual current value with a set current value.

Technical Field

The invention relates to a solution to the problem of excessive power of a direct current motor load at the starting moment, in particular to a control method of the direct current motor load at the starting moment, and belongs to the technical field of starting control of the direct current motor load.

Background

The direct current motor is a quite common motor in life, and the direct current motor is widely used in the industrial field due to the advantages of good speed regulation performance, large torque, low maintenance cost and the like; however, the resistance and the inductance of an armature loop of the direct current motor are both small, and a rotor of the direct current motor has certain mechanical inertia, so that when the direct current motor is powered on, the armature rotating speed and the corresponding counter electromotive force are very small at the initial stage of starting the motor, the starting current is very large and can reach 15-20 times of the rated current to the maximum extent, and the direct current motor can not be started under the condition that some power supplies are insufficient or the capability of a hardware driving circuit of the direct current motor is insufficient; there are currently two solutions to this problem: starting a series resistor and reducing voltage; the series resistor is started, namely, a variable resistor is connected in series in an armature loop, and the starting current is limited within an allowable value by short circuit step by step in the starting process, but the scheme needs to be changed in the motor armature loop and is not suitable for the occasion that the MCU singlechip controls the on-off of a direct current motor driving circuit; and the voltage reduction starting needs to use a single voltage-adjustable direct current power supply to supply power to the motor armature, and is not suitable for the occasion of controlling the on-off of a direct current motor driving circuit by using an MCU singlechip.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a control method of a direct current motor load at the moment of starting, which utilizes the inductive load characteristic of the direct current motor to store energy, adopts a software and hardware matching mode, and a software program of an MCU singlechip periodically and rapidly pushes the motor to rotate for a plurality of times, disconnects the motor load when the load power exceeds a certain value, controls the motor load to be conducted again after short time delay, and circulates for a plurality of times until the motor load is completely pushed, and the current value is gradually stabilized at a rated current value.

The technical scheme adopted by the invention is as follows:

a control method for a direct current motor load at the starting moment comprises the following steps:

(1) the MCU singlechip sends out a conduction control signal to control the conduction of the load of the motor, the motor rotates, and the current is increased;

(2) when the hardware circuit detects that the current is overhigh, the hardware circuit cuts off the load power supply of the motor and feeds an overcurrent signal back to the MCU singlechip, and the motor keeps rotating due to inertia but the rotating speed is rapidly reduced;

(3) the MCU singlechip reads an overcurrent signal and then breaks off the conduction control signal, and after a short time delay, the MCU singlechip sends out the conduction control signal again to control the load of the motor to be conducted when the motor does not stop rotating, and the motor continues to rotate;

(4) and (4) repeating the steps (2) and (3) until the current value is no longer greater than the set maximum current value, the hardware circuit no longer cuts off the power supply of the motor load, the motor starts to normally rotate, and the motor is started.

As further optimization of the invention, the MCU singlechip adopts STM32 series chips.

As a further preferred aspect of the present invention, the software control process of the MCU singlechip employs a programming method of a state machine, the initialization state bit is 0, and the software control process specifically includes:

(1) when the status flag bit is 0, the MCU singlechip sends out a conduction control signal to turn on a load motor, and simultaneously sets the status flag bit to 1 and starts timing;

(2) when the status flag bit is 1, judging whether the timing duration reaches the set duration, if not, continuing timing, otherwise, setting the status flag bit to be 2;

(3) when the status flag bit is 2, judging whether the read feedback signal shows overcurrent or not, if the feedback signal shows no overcurrent, indicating that the motor load works normally, so that the status flag bit and the starting times are initialized for circularly detecting the feedback signal next time; if the feedback signal shows overcurrent, judging whether the starting times are smaller than a set value, if the starting times are larger than the set value, closing the corresponding motor load, setting an overcurrent flag bit of the corresponding motor load, initializing a state flag bit and the starting times, and then not restarting the motor load; if the starting times are less than the set values, closing the corresponding motor load, adding 1 to the starting times, setting the state flag position to be 3 and starting timing;

(4) when the status flag bit is 3, judging whether the timing time length reaches the set time length, if not, continuing timing, otherwise, setting the status flag bit to be 0, and waiting for the next cycle to try to start the motor load again;

(5) when the software has an error, so that the status flag bit is not in the four states of 0, 1, 2 and 3, the status flag bit is reset to 0, and the next cycle of restarting the starting attempt is waited.

As a further preferred aspect of the present invention, the set time period described in steps (2) and (4) of the software control flow is 10 ms.

As a further preferred aspect of the present invention, the hardware circuit in step (2) obtains an actual current value through the sampling resistor and compares the actual current value with a set current value; if the actual current value exceeds the set current value, the hardware circuit cuts off the power supply of the motor load and feeds back an overcurrent signal to the MCU singlechip.

The invention has the beneficial effects that: the inductive load characteristic of the direct current motor is utilized to store energy, a software and hardware matching mode is adopted, the MCU singlechip software program periodically and rapidly pushes the motor to rotate for multiple times, the motor load is disconnected when the load power exceeds a certain value, the motor load is controlled to be conducted again after short time delay, and the process is circulated for multiple times until the motor load is completely pushed, and the current value is gradually stabilized at a rated current value; the motor is pushed again before the motor stops by utilizing the inertia of the motor, so that the starting process of the direct current motor is finished; the problem that the direct current motor load cannot be started due to insufficient power supply power or insufficient direct current motor hardware driving capacity when the MCU singlechip drives the direct current motor load is effectively solved, the power supply or a motor armature loop does not need to be greatly changed, and the direct current motor load starting control circuit has good adaptability to various direct current motors.

Drawings

FIG. 1 is a flow chart of the MCU single chip microcomputer control method of the present invention;

FIG. 2 is a schematic diagram of a hardware circuit of the MCU singlechip control method of the invention.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples.

The embodiment is a method for controlling the load of a direct current motor at the starting moment, which comprises the following steps:

(1) the MCU singlechip sends out a conduction control signal to control the conduction of the load of the motor, the motor rotates, and the current is increased;

(2) when the hardware circuit detects that the current is overhigh, the hardware circuit cuts off the load power supply of the motor and feeds an overcurrent signal back to the MCU singlechip, and the motor keeps rotating due to inertia but the rotating speed is rapidly reduced;

(3) the MCU singlechip reads an overcurrent signal and then breaks off the conduction control signal, and after a short time delay, the MCU singlechip sends out the conduction control signal again to control the load of the motor to be conducted when the motor does not stop rotating, and the motor continues to rotate;

(4) and (4) repeating the steps (2) and (3) until the current value is no longer greater than the set maximum current value, the hardware circuit no longer cuts off the power supply of the motor load, the motor starts to normally rotate, and the motor is started.

The MCU singlechip in this embodiment adopts STM32 series chips.

The hardware circuit in the step (2) of this embodiment obtains an actual current value through a sampling resistor and compares the actual current value with a set current value; if the actual current value exceeds the set current value, the hardware circuit cuts off the power supply of the motor load and feeds back an overcurrent signal to the MCU singlechip.

As shown in fig. 1, in the present embodiment, the software control flow of the MCU singlechip employs a programming method of a state machine, where the initialization state bit is 0, and the software control flow specifically includes:

(1) when the status flag bit is 0, the MCU singlechip sends out a conduction control signal to turn on a load motor, and simultaneously sets the status flag bit to 1 and starts timing;

(2) when the status flag bit is 1, judging whether the timing duration reaches the set duration, if not, continuing timing, otherwise, setting the status flag bit to be 2;

(3) when the status flag bit is 2, judging whether the read feedback signal shows overcurrent or not, if the feedback signal shows no overcurrent, indicating that the motor load works normally, so that the status flag bit and the starting times are initialized for circularly detecting the feedback signal next time; if the feedback signal shows overcurrent, judging whether the starting times are smaller than a set value, if the starting times are larger than the set value, closing the corresponding motor load, setting an overcurrent flag bit of the corresponding motor load, initializing a state flag bit and the starting times, and then not restarting the motor load; if the starting times are less than the set values, closing the corresponding motor load, adding 1 to the starting times, setting the state flag position to be 3 and starting timing;

(4) when the status flag bit is 3, judging whether the timing time length reaches the set time length, if not, continuing timing, otherwise, setting the status flag bit to be 0, and waiting for the next cycle to try to start the motor load again;

(5) when the software has an error, so that the status flag bit is not in the four states of 0, 1, 2 and 3, the status flag bit is reset to 0, and the next cycle of restarting the starting attempt is waited.

In this embodiment, the set duration in the steps (2) and (4) of the software control flow is 10 ms; in practical application, the time length can be adjusted to other set time lengths.

As shown in fig. 2: fig. 2 is a schematic diagram of a hardware circuit collocated with the implementation method, in the diagram, CON _ WW107 is a conduction control signal sent by an MCU singlechip, FB _ WW107 is a feedback signal sent to the MCU singlechip, D _ WW101 is a 110V input power positive, WW102 is a 110V input power negative and a load power negative, and WW107 is a load power positive; the drive chip adopts the EG3002 chip, utilizes the SD foot of the EG3002 chip to carry out load circuit overcurrent protection, and once the load circuit generates overcurrent, the EG3002 chip immediately cuts off output to realize load overcurrent protection.

The invention utilizes the inductive load characteristic of the direct current motor to store energy, adopts a software and hardware matching mode, and the software program of the MCU singlechip periodically and rapidly pushes the motor to rotate for a plurality of times, cuts off the motor load when the load power exceeds a certain value, controls the motor load to be conducted again after short time delay, and circulates for a plurality of times in the way until the motor load is completely pushed, and the current value is gradually stabilized at the rated current value; the motor is pushed again before the motor stops by utilizing the inertia of the motor, so that the starting process of the direct current motor is finished; the problem that the direct current motor load cannot be started due to insufficient power supply power or insufficient direct current motor hardware driving capacity when the MCU singlechip drives the direct current motor load is effectively solved, the power supply or a motor armature loop does not need to be greatly changed, and the direct current motor load starting control circuit has good adaptability to various direct current motors.

The above description is only a preferred embodiment of the present patent, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the inventive concept, and these modifications and decorations should also be regarded as the protection scope of the present patent.