CN107565854B - Impact starting method and system for brushless direct current motor of electric tool - Google Patents
Impact starting method and system for brushless direct current motor of electric tool Download PDFInfo
- Publication number
- CN107565854B CN107565854B CN201710780583.8A CN201710780583A CN107565854B CN 107565854 B CN107565854 B CN 107565854B CN 201710780583 A CN201710780583 A CN 201710780583A CN 107565854 B CN107565854 B CN 107565854B
- Authority
- CN
- China
- Prior art keywords
- motor
- starting
- current
- state
- locked
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000004804 winding Methods 0.000 claims abstract description 15
- 238000010438 heat treatment Methods 0.000 claims description 9
- 230000035939 shock Effects 0.000 claims 3
- 238000010586 diagram Methods 0.000 description 5
- 230000010349 pulsation Effects 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
Landscapes
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention discloses a method and a system for starting a brushless direct current motor of an electric tool through impact. The starting method comprises the following steps: (10) start-up status determination: judging whether a starting working state area of the motor is in a normal starting state or a locked-rotor state according to the rotating speed of the motor in the starting process; and (20) constant current starting: when the motor is in a normal starting state, the motor is controlled to start by adopting continuous current with constant upper limit in a period; (30) pulse current start: when the motor is in a locked-rotor state, the motor is controlled to start by adopting the sectional pulse current. The starting system comprises an inverter (2) electrically connected with the motor (1), a position sensor (3) arranged on an end cover of the motor (1), and a controller (4) respectively electrically connected with the inverter (2) and the position sensor (3). The impact starting method and system for the brushless direct current motor of the electric tool do not increase the power level of components, the switching tube is not easy to damage, and the heat productivity of the motor winding is small.
Description
Technical Field
The invention belongs to the technical field of brushless direct current motor starting control, and particularly relates to a method and a system for starting an impact of a brushless direct current motor of an electric tool, wherein the power level of components is not increased, a switching tube is not easy to damage, and the heating value of a motor winding is small.
Background
Brushless DC motors are used in a large number of electric tools.
The traditional brushless direct current motor control adopts a fixed chopping limit method, which is to draw a current chopping limit according to the load characteristic, and the current is kept continuous in a single commutation period. The control method can generate smoother electromagnetic torque to drive the load, and has higher efficiency and smaller torque pulsation during normal operation. However, since the power tool is often locked, a torque exceeding a rated value is required for the brushless dc motor of the power tool at the time of starting. In order to enable the motor to have large torque to realize starting and overcome stalling, the motor winding needs to have instantaneous large current to generate larger electromagnetic torque. When the electromagnetic torque is larger than the locked-rotor torque, the motor can be rotated. When the motor rotates, the motor is separated from the locked state and enters a normal working state. The conventional method can cause the working current to exceed the rated value, thereby bringing the problems of damage to a switching tube, large heat productivity of a motor winding and the like.
In order to avoid the problem that the device is damaged due to large current caused by motor locked rotation and the heat productivity is overlarge, a device capable of resisting larger current can be adopted. But this greatly increases the product volume and increases the manufacturing cost.
Thus, the prior art has the following problems: because the brushless direct current motor of the electric tool has large locked-rotor current, the problems of damage to a switching tube and overlarge heating value of a motor winding can be caused on the premise of not increasing components.
Disclosure of Invention
The invention aims to provide a brushless direct current motor impact starting method for an electric tool, which does not increase the power level of components, is not easy to damage a switching tube and has small heat productivity of a motor winding.
Another object of the present invention is to provide a brushless dc motor impact starting system for a power tool.
The technical solution for realizing the purpose of the invention is as follows:
a method for starting a brushless direct current motor of an electric tool by impact comprises the following steps:
(10) And (3) starting state determination: judging whether a starting working state area of the motor is in a normal starting state or a locked-rotor state according to the rotating speed of the motor in the starting process;
(20) Constant current starting: when the motor is in a normal starting state, the motor is controlled to start by adopting continuous current with constant upper limit in a period;
(30) Pulse current starts: when the motor is in a locked-rotor state, the motor is controlled to start by adopting the sectional pulse current.
The technical solution for realizing the other purpose of the invention is as follows:
the impact starting system of the brushless direct current motor of the electric tool comprises an inverter 2 electrically connected with a motor 1, a position sensor 3 arranged on an end cover of the motor 1, and a controller 4 electrically connected with the inverter 2 and the position sensor 3 respectively;
the position sensor 3 is used for measuring the position of a motor rotor and obtaining the motor rotating speed so as to distinguish the starting working state of the motor;
the controller 4 is used for judging the starting working state of the motor according to the motor rotating speed in the starting process, and controlling the inverter 2 to respectively generate continuous current or sectional pulse current waveforms with constant upper limit in a period according to different starting states of the motor;
the inverter 2 is used for generating different motor phase current waveforms according to a control signal of the controller 4, and driving the motor 1 to rotate.
Compared with the prior art, the invention has the remarkable advantages that:
1. the volume is not increased: according to the invention, under the condition of encountering locked rotor, the system can generate a larger pulse current under the condition of ensuring the safety of components, so that the motor has larger torque, the locked rotor is overcome, the impact type starting is realized, the large-load starting is realized through the smaller rated components, and the components capable of resisting larger current are not needed, thereby ensuring the body of the original components and not greatly increasing the manufacturing cost;
2. the element is not easy to damage: when the locked rotor is started, a pulse current mode is adopted, so that the current has a high-amplitude pulse to enable the motor to have larger electromagnetic torque, and meanwhile, a period of zero current is caused by switching off of a switching tube, so that the average value or the mean square value of the current accords with the upper limit of each component, and each component is protected from being damaged; for protection of the power tube, parameters can be obtained by inquiring a data table provided by a manufacturer, and the current value allowed to pass by the power tube increases along with the reduction of the on time or the duty cycle. According to the two parameters, the amplitude and the pulse width of the pulse current are calculated, so that the locked rotor can be overcome under the condition of ensuring the safety of the device, and the pulse type starting is realized.
3. The heat productivity of the motor winding is small: when the motor is locked, the loss of the motor is mainly copper loss, namely the heating value of the whole motor is mainly derived from the heating of the internal resistance of the winding, and the heating power is in direct proportion to the square of the current. The root mean square of the current in one period is equal to the rated value, so that the reliable use of the motor winding can be ensured.
The invention is described in further detail below with reference to the drawings and the detailed description.
Drawings
Fig. 1 is a flowchart of a method for starting a brushless dc motor of an electric tool according to the present invention.
Fig. 2 is a waveform diagram of constant current start.
Fig. 3 is a waveform diagram of the pulse current start.
Fig. 4 is a schematic structural diagram of a brushless dc motor impact starting system of the electric tool according to the present invention.
In the figure, 1 motor, 2 inverter, 3 position sensor, 4 controller.
Detailed Description
As shown in fig. 1, the method for starting the brushless dc motor of the electric tool according to the present invention comprises the following steps:
(10) And (3) starting state determination: judging whether a starting working state area of the motor is in a normal starting state or a locked-rotor state according to the rotating speed of the motor in the starting process;
when the motor speed is lower than 1000rpm, the motor is determined to be in a locked state.
When the motor rotation speed reaches 1000rpm and above, the motor is determined to be in a normal starting state.
Judging the working state of the motor rotor by judging whether the speed or the position of the motor rotor is changed or not: if the rotating speed is too low or the position is almost unchanged, judging that the rotating speed is in a locked state, otherwise, if the rotating speed is normally lifted or is stable, judging that the rotating speed is in a normal working state.
In the state measuring step (10), when the measured rotational speed of the motor rotor is lower than the expected rotational speed of 1000rpm or the position change of the point on the circumference of the motor rotor within 0.1s is smaller than 120 DEG electric angle, the motor is determined to be in a locked-rotor state.
(20) Constant current starting: when the motor is in a normal starting state, the motor is controlled to start by adopting continuous current with constant upper limit in a period;
for normal working state, a constant current working mode, namely fixed current limit chopping control is adopted, so that current in a commutation period is continuous, pulsation is small, and the work is stable.
(30) Pulse current starts: when the motor is in a locked-rotor state, the motor is controlled to start by adopting the sectional pulse current.
The step of starting (30) the pulse current is specifically to control the starting torque of the motor by using the pulse current for keeping the upper limit of the phase current of the brushless motor constant, thereby controlling the starting of the motor. The pulse current refers to changing a constant current waveform in a phase period into a plurality of segmented pulse current waveforms.
The amplitude and the pulse time width of the pulse current are determined according to a current protection threshold value of a power component of the brushless motor system or a blocking torque value of the electric tool, or according to the same principle that windings generate heat, the root mean square of the amplitude and the pulse width of the pulse current is equal to the amplitude of the constant current.
Preferably, the method comprises the steps of,
in the step of starting the pulse current (30), the pulse current form control is to drive the motor by adopting the pulse current, and the root mean square of the pulse current period is equal to the rated value.
Preferably, the method comprises the steps of,
the amplitude and the pulse width of the pulse current are determined according to the current protection value of the components preset by the system.
For the locked-rotor state, the driver will control the motor to adopt a pulsed current mode of operation to overcome the locked-rotor torque. According to the current protection value of the components preset by the system, the amplitude value and the pulse width of the current pulse are determined, so that the motor has larger pulse torque, and the impact type starting is realized.
The method of the invention has simple control, can realize large-load starting through a device with smaller quota, reduces the cost and reduces the volume
Fig. 2 is a waveform diagram of constant current start.
Fig. 3 is a waveform diagram of the pulse current start.
When the motor is in a rated working state, a fixed chopper limit method is adopted, so that the motor winding is kept continuously and smoothly in a commutation period, and the motor winding has higher efficiency and smaller torque pulsation during normal working; when the motor is started, a pulse current mode is adopted, so that the current has a high-amplitude pulse, the motor has larger electromagnetic torque, and meanwhile, a period that the current is zero is provided when the switching tube is turned off, so that the average value or the mean square value of the current accords with the upper limit of each component, and each component is protected.
When the motor is locked, the loss of the motor is mainly copper loss, namely the heating value of the whole motor is mainly derived from the heating of the internal resistance of the winding, and the heating power is in direct proportion to the square of the current. The control mode is set, so that the root mean square of the current in one period is equal to the rated value, and the reliable use of the motor winding can be ensured. For protection of the power tube, parameters can be obtained by inquiring a data table provided by a manufacturer, and the current value allowed to pass by the power tube increases along with the reduction of the on time or the duty cycle. According to the two parameters, the amplitude and the pulse width of the pulse current are calculated, so that the locked rotor can be overcome under the condition of ensuring the safety of the device, and the pulse type starting is realized.
As shown in fig. 4, the brushless dc motor impact starting system of the electric tool of the present invention comprises an inverter 2 electrically connected to a motor 1, a position sensor 3 disposed on an end cover of the motor 1, and a controller 4 electrically connected to the inverter 2 and the position sensor 3, respectively;
the position sensor 3 is used for measuring the position of a motor rotor and obtaining the motor rotating speed so as to distinguish the starting working state of the motor;
the controller 4 is used for judging the starting working state of the motor according to the motor rotating speed in the starting process, and controlling the inverter 2 to respectively generate continuous current or sectional pulse current waveforms with constant upper limit in a period according to different starting states of the motor;
the inverter 2 is used for generating different motor phase current waveforms according to a control signal of the controller 4, and driving the motor 1 to rotate.
The starting working state of the motor is divided into a normal starting state and a locked-rotor state;
when the rotating speed of the motor is lower than 1000rpm, determining that the motor is in a locked-rotor state;
when the motor rotation speed reaches 1000rpm and above, the motor is determined to be in a normal starting state.
In general, the inverter 2 is externally connected with a dc power supply, which is common knowledge in the art and will not be described in detail.
Claims (5)
1. The impact starting method of the brushless direct current motor of the electric tool is characterized by comprising the following steps of:
(10) And (3) starting state determination: judging whether a starting working state area of the motor is in a normal starting state or a locked-rotor state according to the rotating speed of the motor in the starting process;
(20) Constant current starting: when the motor is in a normal starting state, the motor is controlled to start by adopting continuous current with constant upper limit in a period;
(30) Pulse current starts: when the motor is in a locked-rotor state, the motor is controlled to start by adopting a sectional pulse current;
the step of starting the pulse current (30) is specifically to control the starting torque of the motor by adopting the pulse current which enables the upper limit of the phase current of the brushless motor to be constant, thereby controlling the starting of the motor; the pulse current refers to changing a constant current waveform in a phase period into a plurality of segmented pulse current waveforms;
the amplitude and the pulse time width of the pulse current are determined according to the same principle of heating of the winding, and the root mean square of the amplitude and the pulse width of the pulse current is equal to the amplitude of the constant current.
2. The shock start method according to claim 1, wherein:
in the step (10) of determining the starting state, when the rotating speed of the motor is lower than 1000rpm, the motor is determined to be in a locked-rotor state.
3. The shock start method according to claim 1, wherein:
in the step of determining the starting state (10), when the motor rotation speed reaches 1000rpm or more, the motor is determined to be in a normal starting state.
4. A power tool brushless dc motor impact starting system based on the power tool brushless dc motor impact starting method according to any one of claims 1-3, characterized in that:
comprises an inverter (2) electrically connected with a motor (1), a position sensor (3) arranged on an end cover of the motor (1), and a controller (4) respectively electrically connected with the inverter (2) and the position sensor (3);
the position sensor (3) is used for measuring the position of a motor rotor and obtaining the motor rotating speed so as to distinguish the starting working state of the motor;
the controller (4) is used for judging the starting working state of the motor according to the motor rotating speed in the starting process and controlling the inverter (2) to respectively generate continuous current or sectional pulse current waveforms with constant upper limit in a period according to different starting states of the motor;
the inverter (2) is used for generating different motor phase current waveforms according to a control signal of the controller (4) to drive the motor (1) to rotate.
5. The shock start system according to claim 4, wherein:
the starting working state of the motor is divided into a normal starting state and a locked-rotor state;
when the rotating speed of the motor is lower than 1000rpm, determining that the motor is in a locked-rotor state;
when the motor rotation speed reaches 1000rpm and above, the motor is determined to be in a normal starting state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710780583.8A CN107565854B (en) | 2017-09-01 | 2017-09-01 | Impact starting method and system for brushless direct current motor of electric tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710780583.8A CN107565854B (en) | 2017-09-01 | 2017-09-01 | Impact starting method and system for brushless direct current motor of electric tool |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107565854A CN107565854A (en) | 2018-01-09 |
| CN107565854B true CN107565854B (en) | 2024-01-30 |
Family
ID=60979034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710780583.8A Active CN107565854B (en) | 2017-09-01 | 2017-09-01 | Impact starting method and system for brushless direct current motor of electric tool |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107565854B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109782643B (en) * | 2019-03-12 | 2022-04-15 | 常州彤扬电气制造有限公司 | Control method for starting heat engine of electric tool |
| CN111938508B (en) * | 2019-05-15 | 2024-03-08 | 添可智能科技有限公司 | Floor brush type identification method, dust collection equipment and storage medium |
| CN112821845B (en) * | 2019-11-18 | 2024-02-23 | 南京泉峰科技有限公司 | Electric tool control method and electric tool |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001298982A (en) * | 2000-04-17 | 2001-10-26 | Matsushita Electric Ind Co Ltd | Motor drive, and motor unit comprising it |
| CN1356765A (en) * | 2000-11-24 | 2002-07-03 | 开关磁阻驱动有限公司 | Current chopping in switch magnetoresistance driven system |
| CN1875539A (en) * | 2003-12-01 | 2006-12-06 | 罗姆股份有限公司 | DC motor drive device |
| JP2007151267A (en) * | 2005-11-25 | 2007-06-14 | Mitsuba Corp | Motor drive |
| CN201656891U (en) * | 2010-03-17 | 2010-11-24 | 保定维特瑞交通设施工程有限责任公司 | Pulse controller for direct-current motor |
| CN202841040U (en) * | 2012-03-05 | 2013-03-27 | 绍兴光大芯业微电子有限公司 | Control circuit for reducing power consumption when direct current motor is blocked |
| CN103684140A (en) * | 2013-12-10 | 2014-03-26 | 吴凯 | Brushless direct current motor, method for positioning position of rotor of brushless direct current motor and method for starting brushless direct current motor |
| CN103812390A (en) * | 2014-02-28 | 2014-05-21 | 捷和电机制品(深圳)有限公司 | Method used for starting brushless direct current motor and applied to mixer and mixer |
| CN105207531A (en) * | 2015-09-11 | 2015-12-30 | 厦门唯科健康科技有限公司 | Soft start method for motor |
| CN207200603U (en) * | 2017-09-01 | 2018-04-06 | 苏州亮明工具有限公司 | Electric tool brshless DC motor impacting start system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2186182A4 (en) * | 2007-08-14 | 2013-03-13 | Ramu Inc | Method, controller, and power converter for controlling a single-switch based switched reluctance machine |
-
2017
- 2017-09-01 CN CN201710780583.8A patent/CN107565854B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001298982A (en) * | 2000-04-17 | 2001-10-26 | Matsushita Electric Ind Co Ltd | Motor drive, and motor unit comprising it |
| CN1356765A (en) * | 2000-11-24 | 2002-07-03 | 开关磁阻驱动有限公司 | Current chopping in switch magnetoresistance driven system |
| CN1875539A (en) * | 2003-12-01 | 2006-12-06 | 罗姆股份有限公司 | DC motor drive device |
| JP2007151267A (en) * | 2005-11-25 | 2007-06-14 | Mitsuba Corp | Motor drive |
| CN201656891U (en) * | 2010-03-17 | 2010-11-24 | 保定维特瑞交通设施工程有限责任公司 | Pulse controller for direct-current motor |
| CN202841040U (en) * | 2012-03-05 | 2013-03-27 | 绍兴光大芯业微电子有限公司 | Control circuit for reducing power consumption when direct current motor is blocked |
| CN103684140A (en) * | 2013-12-10 | 2014-03-26 | 吴凯 | Brushless direct current motor, method for positioning position of rotor of brushless direct current motor and method for starting brushless direct current motor |
| CN103812390A (en) * | 2014-02-28 | 2014-05-21 | 捷和电机制品(深圳)有限公司 | Method used for starting brushless direct current motor and applied to mixer and mixer |
| CN105207531A (en) * | 2015-09-11 | 2015-12-30 | 厦门唯科健康科技有限公司 | Soft start method for motor |
| CN207200603U (en) * | 2017-09-01 | 2018-04-06 | 苏州亮明工具有限公司 | Electric tool brshless DC motor impacting start system |
Non-Patent Citations (2)
| Title |
|---|
| L. Pravica et al..Flying Start of a Permanent Magnet Wind Power Generator Based on a Discontinuous Converter Operation Mode and a Phase-Locked Loop.IEEE Transactions on Industrial Electronics.2017,第65卷(第2期),第1097-1106页. * |
| 张文海.PWM无刷直流力矩电动机绕组内部电流的计算.电世界.2008,第第49卷卷(第第05期期),第46-47页. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107565854A (en) | 2018-01-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2915631B1 (en) | Electric tool | |
| EP2625778B1 (en) | Control of an electrical machine | |
| US6943510B2 (en) | Excitation circuit and control method for flux switching motor | |
| CN107565854B (en) | Impact starting method and system for brushless direct current motor of electric tool | |
| CN101485076B (en) | Method for controlling a deceleration process of a DC motor and controller | |
| US20030042859A1 (en) | Excitation circuit and control method for flux switching motor | |
| CN108233797A (en) | Electric tool | |
| CN106428200B (en) | Multi-phase motor control method, controller and polyphase machine electric powered steering pumping system | |
| US8339075B2 (en) | Method for controlling a deceleration process of a DC motor and controller | |
| WO2018082496A1 (en) | Electric tool and control method therefor | |
| CN207200603U (en) | Electric tool brshless DC motor impacting start system | |
| CN102751921B (en) | Method for controlling winding current waveforms of switched reluctance motor | |
| CN109510405B (en) | Non-inductive brushless motor and anti-stalling control method thereof | |
| CN105515493B (en) | Electric pick switched reluctance variable speed machine controller | |
| CN104092412A (en) | Method and device for setting upper limit of brushless motor phase lead angle and control system | |
| CN113785485A (en) | Sensorless motor control for power tools | |
| JP2017200337A (en) | Motor drive device | |
| CN112436760A (en) | Motor control device, method and system, household appliance and storage medium | |
| CN110311614B (en) | Control method for inhibiting torque pulsation of switched reluctance motor | |
| EP4307555A1 (en) | Power tool | |
| CN114079407A (en) | Electric tool and electric tool control method | |
| CN104242778A (en) | Processing method for motor system to deal with unstable power supply |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |