CN109921695B

CN109921695B - Brushless motor starting method

Info

Publication number: CN109921695B
Application number: CN201910057251.6A
Authority: CN
Inventors: 张磊
Original assignee: Blue Ocean Intelligent Technology Hangzhou Co ltd
Current assignee: Blue Ocean Intelligent Technology Hangzhou Co ltd
Priority date: 2019-01-21
Filing date: 2019-01-21
Publication date: 2023-04-28
Anticipated expiration: 2039-01-21
Also published as: CN109921695A

Abstract

Because the output power of the motor is different when the motor is started and normally operated, the power is continuously increased from zero when the motor is started, the power is more stable when the motor is normally operated, the motor rotation speed is continuously increased when the motor is started, and the motor rotation speed is more stable when the motor is normally operated; therefore, the same excitation driving time sequence given by the motor in starting and normal running can cause unstable motor running; the invention discloses a starting method of a brushless motor, wherein a motor starting circuit comprises the brushless motor, a Hall sensor, an inverter, a driving circuit and a controller, wherein the brushless motor comprises a rotor and 2 stator winding coils which are connected in series.

Description

Brushless motor starting method

Technical Field

The invention relates to the technical field of starting of motors, in particular to a starting method of a direct current motor.

Background

Because the motor has difference in output power when starting and normal operation, the power is continuously increased from zero when starting, and the power is more stable when normal operation. The same excitation drive timing imparted by the motor at start-up and normal operation can result in unstable motor operation. In addition, if the acceleration at the time of starting is large, noise is large.

In the prior art, the motor is started by adopting the same excitation driving time sequence as the motor in normal operation, namely, in a motor starting stage and a motor normal operation stage, all paths of control signals sent by a main controller are the same, and the sending sequence of all paths of control signals and the duty ratio of all paths of control signals are the same. By adopting the driving mode, the problems of unstable motor operation and high noise during starting exist.

Disclosure of Invention

In order to improve the stability of the motor during starting and reduce the noise during starting, the invention provides a starting mode of the motor.

The technical scheme adopted for solving the technical problems is as follows:

the motor starting circuit comprises a brushless motor, a Hall sensor, an inverter, a driving circuit and a controller, wherein the brushless motor comprises a rotor and 2 stator winding coils connected in series, the rotor is a permanent magnet with two pairs of magnetic poles, and the motor starting mode is as follows: firstly, a controller detects signals output by a Hall sensor, current in a set direction is generated according to the detected Hall signals, a stator winding generates a rotating magnetic field to enable a rotor to start rotating, the excitation pulse width duty ratio of the stator winding is one fourth or less than one fourth of the excitation pulse width duty ratio of the stator winding when the motor is in normal operation, the excitation period is one fourth of the excitation period when the motor is in normal operation, or less than one fourth of the excitation period when the motor is in normal operation, after starting, the controller detects the Hall signals at regular time, if the detected Hall signals are changed, driving is completed, a normal working mode is entered, and if the detected Hall signals are unchanged; and continuing to drive to generate current in the direction opposite to the original set direction, detecting the Hall signal by the controller at fixed time until the detected Hall signal is changed, starting and ending, and enabling the motor to enter a normal working mode.

The excitation period is the sum of excitation time and follow current time, in the excitation time, two driving geminate transistors are simultaneously started, current is continuously increased, a power supply continuously transmits electric energy to the inside of a stator winding, and a motor stator winding continuously stores electromagnetic energy and outputs mechanical energy; in the follow current time, the two upper driving pipes are closed at the same time, the two lower driving pipes are opened at the same time, the current is continuously reduced, the power supply stops supplying energy to the motor, and the motor stator winding continuously outputs mechanical energy to the outside until the electromagnetic energy stored in the stator in the earlier stage is exhausted. The invention shortens the excitation period to ensure that the input of electric energy and mechanical energy and the energy consumed by the running work of the device are in dynamic balance, thereby ensuring the stable rotation of the motor.

The technical scheme of the invention has the following positive effects:

(1) The motor can be ensured to stably run in the starting stage;

(2) Noise generated when the motor is started is reduced;

(3) Reducing mechanical shock during start-up.

Drawings

FIG. 1 is a logic block diagram of motor start

Detailed Description

One embodiment of the invention is:

the motor starting circuit comprises a brushless motor, a Hall sensor, an inverter, a driving circuit and a controller, wherein the brushless motor comprises a rotor and 2 stator winding coils connected in series. As shown in fig. 1, the driving motor starts to start (enter state 1), and first, the output hall signal of the hall sensor is detected (enter state 2), and the hall signal is determined to be high? (entering state 3), if the hall signal is high, the stator winding is excited by the clockwise current generated by the driving (entering state 4), so that the rotor rotates in a preset direction by the rotating magnetic field generated by the stator, at this time, in order to improve the stability during starting, the duty ratio of the excitation signal takes one eighth (1/2 in normal operation), the starting excitation period is one fourth of the excitation period during normal operation of the motor, after starting, the hall signal is detected by the controller at regular time, and the master controller judges that the hall signal is low? (enter state 6) if the hall signal goes low, i.e. the hall signal has changed, indicating that the rotor has rotated to the next polarity region, then it is decided that the start-up procedure is over (enter state 8) and the normal operation mode is subsequently entered (enter state 9). In state 6, if the hall signal is high, the drive produces a counter-clockwise current to energize the stator winding (enter state 5), the controller detects the hall signal at regular time, the master determines that the hall signal is high? If the hall signal is high, the start is over, if the hall signal is low, the drive produces a clockwise current to energize the stator windings (enter state 4), and the process of cycling through the start is entered as analyzed above.

If in state 2, the detection of the hall signal is started, and the hall signal is judged to be high? (entering state 3), if the current is low, the stator winding is excited by driving the current generating the reverse clock direction (entering state 5), then the rotor rotates towards the preset direction by the rotating magnetic field generated by the stator, at the moment, in order to improve the stability during starting, the duty ratio of an excitation signal is one eighth (1/2 in normal operation), the starting excitation period is one fourth of the excitation period during normal operation of the motor, after starting, the controller detects the Hall signal at regular time, and the main controller judges that the Hall signal is high? (enter state 7) if the hall signal goes high, i.e. the hall signal has changed, indicating that the rotor has rotated to the next polarity region, then it is decided that the start-up procedure is over (enter state 8) and the normal operation mode is subsequently entered (enter state 9). In state 7, if the hall signal is low, the drive produces clockwise current to energize the stator winding (entering state 4), the controller detects the hall signal at regular time, and the master determines that the hall signal is low? If the hall signal is low, the start-up is over, and if the hall signal is high, the drive produces a counter-clockwise current to energize the stator windings (enter state 5), and the process of cyclic start-up is entered as analyzed above.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and variations can be made by those skilled in the art without departing from the principles of the present invention, which is to be considered as the scope of the present invention.

Claims

1. The motor starting circuit comprises a brushless motor, a Hall sensor, an inverter, a driving circuit and a controller, wherein the brushless motor comprises a rotor and 2 stator winding coils connected in series, and is characterized in that firstly, the controller detects signals output by the Hall sensor, drives and generates current in a set direction according to the detected Hall signals, the stator winding generates a rotating magnetic field to enable the rotor to start rotating, the excitation pulse width of the stator winding when the motor is started is one fourth or less than one fourth of the excitation pulse width of the stator winding when the motor is normally operated, the excitation period of the motor is one fourth or less than one fourth of the excitation period when the motor is normally operated, the controller detects the Hall signals at regular time after starting, if the detected Hall signals change, the driving is completed, the starting is completed, and the motor enters a normal working mode; if the detected Hall signal is unchanged; and continuing to drive to generate current in the direction opposite to the original set direction, detecting the Hall signal by the controller at fixed time until the detected Hall signal is changed, starting and ending, and enabling the motor to enter a normal working mode.