WO2019210790A1 - 电动工具及其控制方法 - Google Patents

电动工具及其控制方法 Download PDF

Info

Publication number
WO2019210790A1
WO2019210790A1 PCT/CN2019/083863 CN2019083863W WO2019210790A1 WO 2019210790 A1 WO2019210790 A1 WO 2019210790A1 CN 2019083863 W CN2019083863 W CN 2019083863W WO 2019210790 A1 WO2019210790 A1 WO 2019210790A1
Authority
WO
WIPO (PCT)
Prior art keywords
control signal
power tool
tool according
low side
side switch
Prior art date
Application number
PCT/CN2019/083863
Other languages
English (en)
French (fr)
Inventor
王宏伟
杨德中
孙永安
Original Assignee
南京德朔实业有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 南京德朔实业有限公司 filed Critical 南京德朔实业有限公司
Priority to EP19796882.9A priority Critical patent/EP3780379B1/en
Priority to CN201980007469.9A priority patent/CN111630770B/zh
Publication of WO2019210790A1 publication Critical patent/WO2019210790A1/zh
Priority to US17/080,978 priority patent/US11070164B2/en
Priority to US17/354,784 priority patent/US11637523B2/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/08—Arrangements for controlling the speed or torque of a single motor
    • H02P6/085—Arrangements for controlling the speed or torque of a single motor in a bridge configuration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B45/00—Hand-held or like portable drilling machines, e.g. drill guns; Equipment therefor
    • B23B45/02—Hand-held or like portable drilling machines, e.g. drill guns; Equipment therefor driven by electric power
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D45/00—Sawing machines or sawing devices with circular saw blades or with friction saw discs
    • B23D45/16—Hand-held sawing devices with circular saw blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D49/00—Machines or devices for sawing with straight reciprocating saw blades, e.g. hacksaws
    • B23D49/10—Hand-held or hand-operated sawing devices with straight saw blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
    • B24B23/02—Portable grinding machines, e.g. hand-guided; Accessories therefor with rotating grinding tools; Accessories therefor
    • B24B23/028—Angle tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B19/00—Impact wrenches or screwdrivers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
    • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
    • H02P29/60—Controlling or determining the temperature of the motor or of the drive
    • H02P29/68—Controlling or determining the temperature of the motor or of the drive based on the temperature of a drive component or a semiconductor component
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
    • H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
    • H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power
    • H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
    • H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
    • H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
    • H02P7/29—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using pulse modulation

Definitions

  • the present disclosure relates to a power tool and a control method thereof, and in particular to a power tool capable of suppressing temperature rise and power loss of a switch and a control method thereof.
  • the power tool is usually moved by a motor-driven function to realize the function of the power tool.
  • the motor can be a brushless motor or a brushed motor.
  • the drive circuit is usually controlled by an inverter drive bridge circuit, and the power components of the inverter drive bridge circuit, that is, switches (MOSFET, IGBT, etc.) usually generate a large amount of heat. Since the switch has a parasitic diode, when the switch is switched from the on state to the off state, since the current cannot be transient, the current in the motor winding passes through the parasitic diode of the other switch, and the parasitic diode generates heat due to the internal resistance, so that The parasitic diode switch and the drive circuit temperature rise. In particular, in the case of heavy load and high current, the heat loss is more serious.
  • an object of the present disclosure is to provide a power tool capable of suppressing switching temperature rise and power loss and a control method thereof.
  • a power tool comprising: a function for realizing the function of the power tool; a motor for driving the function, the motor comprising a plurality of windings; and a power module for supplying a supply current, including the first a power supply end and a second power supply end; a driving circuit electrically connected to the motor, the driving circuit comprising: a first driving end electrically connected to the first power end; a second driving end, and the second The high-side switch is electrically connected to the first driving end; the plurality of low-side switches are respectively connected to the low-side end of the low-side switch.
  • the controller is configured to: output a first control signal to one of the high side switches to cause one of the high side switches to be in an on state or an off state; Outputting a second control signal to one of the low side switches such that one of the low side switches is in the other of the on and off states; wherein the low side of one of the high side switches Connected to one of the low side switches A high-side end.
  • the first control signal output by the controller is a first PWM signal; and the second control signal output by the controller is a second PWM signal.
  • the duty ratio of the first PWM signal ranges from 20% to 90%.
  • the duty ratio of the first PWM signal ranges from 10% to 95%.
  • the duty ratio of the first PWM signal ranges from 30% to 95%.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset duration.
  • the first preset duration ranges from 5 microseconds to 10 microseconds.
  • a rising edge of the first control signal is spaced apart from a falling edge of the second control signal by a second predetermined duration.
  • the second preset duration ranges from 5 microseconds to 30 microseconds.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset duration, and a rising edge of the first control signal and the second control signal are The falling edges are separated by a second preset duration.
  • the ratio of the first preset duration to the second preset duration is less than or equal to 1.
  • the controller synchronously outputs the first control signal and the second control signal.
  • a sum of a duty ratio of the first PWM signal and a duty ratio of the second PWM signal is less than 100%.
  • the duty ratio of the second PWM signal ranges from 20% to 90%.
  • the duty ratio of the second PWM signal ranges from 10% to 95%.
  • the duty ratio of the second PWM signal ranges from 30% to 95%.
  • the power tool further includes: a current measurement module for detecting or estimating a phase current; the controller being configured to: when the phase current is less than or equal to zero, the controller is configured to be in the When the phase current is less than or equal to zero, the controller is configured to output a second control signal to turn off one of the low side switches, or to output a first control signal control to turn off one of the high side switches.
  • a current measurement module for detecting or estimating a phase current
  • the controller being configured to: when the phase current is less than or equal to zero, the controller is configured to be in the When the phase current is less than or equal to zero, the controller is configured to output a second control signal to turn off one of the low side switches, or to output a first control signal control to turn off one of the high side switches.
  • the controller includes a temperature sensor disposed inside the controller, the controller estimates a temperature of the driving circuit according to a detected value of the temperature sensor, and a temperature detection value of the driving circuit exceeds a preset threshold The controller controls the drive circuit to stop working.
  • Another power tool includes: a function for realizing the function of the power tool; a motor for driving the function, the motor including a plurality of windings; and a power module for supplying a supply current, including a power supply end and a second power supply end; a driving circuit electrically connected to the motor, comprising: a first driving end electrically connected to the first power end; and a second driving end electrically connected to the second power end a first high side switch, the high side end of the first high side switch is electrically connected to the first driving end; the first low side switch, the low side end of the first low side switch is electrically connected Connected to the second driving end; the controller is configured to: output a first control signal to the first high side switch to bring the first high side switch into an on state or an off state; output a second Controlling a signal to the first low side switch to cause the first low side switch to be in another of an on or off state; wherein a low side end of the first high side switch is coupled to the first The high side of the low
  • the driving circuit further includes a second low side switch, the low side end of the second low side switch is electrically connected to the second driving end; the controller is configured to: output the first a control signal to the first high side switch and the second low side switch to constitute a first current loop; in the first current loop, a supply current provided by the power module is sequentially passed through the first drive The end, the first high side switch, the winding, the second low side switch, and the second drive end.
  • the first control signal output by the controller is a first PWM signal; and the second control signal output by the controller is a second PWM signal.
  • the duty ratio of the first PWM signal ranges from 20% to 90%.
  • the duty ratio of the first PWM signal ranges from 10% to 95%.
  • the duty ratio of the first PWM signal ranges from 30% to 95%.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset duration.
  • the first preset duration ranges from 5 microseconds to 10 microseconds.
  • a rising edge of the first control signal is spaced apart from a falling edge of the second control signal by a second predetermined duration.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset duration, and a rising edge of the first control signal and the second control signal are The falling edges are separated by a second preset duration.
  • the ratio of the first preset duration to the second preset duration is less than or equal to 1.
  • the controller synchronously outputs the first control signal and the second control signal.
  • a sum of a duty ratio of the first PWM signal and a duty ratio of the second PWM signal is less than 100%.
  • the duty ratio of the second PWM signal ranges from 20% to 90%.
  • the duty ratio of the second PWM signal ranges from 10% to 95%.
  • the duty ratio of the second PWM signal ranges from 30% to 95%.
  • the power tool further includes: a current measurement module for detecting or estimating a phase current; the controller being configured to: when the phase current is less than or equal to zero, the controller is configured to be in the When the phase current is less than or equal to zero, the controller is configured to output a second control signal to turn off one of the low side switches, or to output a first control signal control to turn off one of the high side switches. .
  • a current measurement module for detecting or estimating a phase current
  • the controller being configured to: when the phase current is less than or equal to zero, the controller is configured to be in the When the phase current is less than or equal to zero, the controller is configured to output a second control signal to turn off one of the low side switches, or to output a first control signal control to turn off one of the high side switches.
  • a method of controlling a power tool comprising: a driving circuit, comprising: a first driving end electrically connected to the first power end; and a second driving end electrically connected to the second power end a plurality of high-side switches, the high-side switch includes a high-side end and a low-voltage end, the high-side end of the high-side switch being electrically connected to the first driving end, respectively; and a plurality of low-side switches, the low The side switch includes a high side end and a low voltage end, and the low side end is electrically connected to the second driving end respectively; the control method of the electric tool includes: turning one of the high side switches into a conductive state or a shutdown state; causing one of the low side switches to be in another of an on state and an off state; wherein a low side end of one of the high side switches is coupled to one of the low side switches High side.
  • the first control signal is a first PWM signal; and the second control signal is a second PWM signal.
  • the duty ratio of the first PWM signal ranges from 20% to 90%.
  • the duty ratio of the first PWM signal ranges from 10% to 95%.
  • the duty ratio of the first PWM signal ranges from 30% to 95%.
  • a falling edge of the first control signal and a rising edge of the second control signal are separated by a first predetermined duration.
  • the first preset duration ranges from 5 microseconds to 10 microseconds.
  • a rising edge of the first control signal is spaced apart from a falling edge of the second control signal by a second predetermined duration.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset duration, and a rising edge of the first control signal and the second control signal are The falling edges are separated by a second preset duration.
  • the ratio of the first preset duration to the second preset duration is less than or equal to 1.
  • a sum of a duty ratio of the first PWM signal and a duty ratio of the second PWM signal is less than 100%.
  • the duty ratio of the second PWM signal ranges from 20% to 90%.
  • the duty ratio of the second PWM signal ranges from 10% to 95%.
  • the duty ratio of the second PWM signal ranges from 30% to 95%.
  • the second control signal turns off one of the low side switches when the phase current is less than or equal to zero, or the first control signal turns off one of the high side switches.
  • the present disclosure is advantageous in that it is possible to suppress the temperature rise of the drive circuit and the switch and reduce the power loss.
  • FIG. 1 is a perspective view of an electric power tool according to an embodiment
  • FIG. 2 is a perspective view of another embodiment of a power tool
  • Figure 3 is a perspective view of another embodiment of the power tool
  • FIG. 4 is a circuit diagram of a power tool of an embodiment
  • Figure 5 is a simplified diagram of the drive circuit of Figure 4.
  • Figure 6a is a waveform diagram of a control signal of a conventional driving circuit
  • Figure 6b is a waveform diagram of a control signal of another conventional driving circuit
  • Figure 7a is a current trend indication diagram when the motor driving state is in the AB state
  • Figure 7b is a current trend indication diagram when the motor driving state is in an AC state
  • Figure 8 is a current trend indication diagram of a motor that cannot be transiently switched from an AB state to an AC state;
  • FIG. 9 is a waveform diagram of a control signal applied to a control terminal of each switch by a controller of the present disclosure.
  • FIG. 10 is a waveform diagram of a first control signal and a second control signal of an embodiment
  • FIG. 11 is a waveform diagram of a first control signal and a waveform diagram of a second control signal of another embodiment
  • Figure 12a is an actual waveform diagram of a conventional control signal applied to the control terminal AH of the high side switch Q1 and an actual waveform diagram of a control signal applied to the control terminal AL of the low side switch Q2;
  • Figure 12b is a current trace diagram of the conventional control signal of Figure 12a causing a short circuit phenomenon
  • Figure 13a is a waveform diagram of the current I1 of the winding at the time of heavy load and the current I2 of the winding at the time of light load;
  • Figure 13b is a diagram showing a relationship between a first control signal applied to the control terminal AH of the high-side switch Q1 and a second control signal applied to the control terminal AL of the low-side switch Q2 and the motor output torque;
  • Fig. 13c is a diagram showing a relationship between a control signal applied to the control terminal AH of the high side switch Q1 and the control terminal AL applied to the low side switch Q2 and the motor output torque in another embodiment.
  • the power tool of the present disclosure may be a hand-held power tool, a garden type tool, a garden type vehicle such as a vehicle type lawn mower, and is not limited herein.
  • the power tool 10 of the present disclosure includes, but is not limited to, the following: a screwdriver, an electric drill, a wrench, an angle grinder, etc., a power tool that requires speed control, a sanding machine, and the like, which may be used to polish a workpiece, a reciprocating saw, a circular saw, and a curve.
  • a saw or the like may be used to cut a workpiece; a power tool such as a hammer that may be used for impact.
  • These tools may also be garden tools such as pruning machines, chain saws, and vehicle mowers; these tools may also be used for other purposes, such as blenders.
  • these power tools 10 can adopt the substance of the technical solutions disclosed below, it can fall within the protection scope of the present disclosure.
  • the power tool 10 includes, but is not limited to, a housing 11, a function member 12, and a motor 13.
  • the housing 11 constitutes a main body portion of the electric power tool 10 for accommodating the motor 13. One end of the housing 11 is also used to mount the functional component 12.
  • the functional component 12 is used to implement the functions of the power tool 10, such as sanding, cutting, and the like.
  • the power tool 10 shown in FIG. 1 is exemplified by a hand-held electric drill, and the function member 12 is a drill bit.
  • the functional component 12 is operatively coupled to the motor 13, for example, to the motor 13 via a tool accessory shaft.
  • the motor 13 is used to drive the functional component 12 to drive the functional component 12 to operate to power the functional component 12.
  • the motor 13 includes a motor shaft, a rotor, a stator, and a multi-phase winding (Figs. 4 and 5) that is operatively coupled to the functional component 12, such as a motor shaft through the transmission 14 and a tool that supports the functional component.
  • the accessory shaft transmits the driving force of the motor shaft to the tool accessory shaft, so that the functional component 12 mounted on the tool accessory shaft operates.
  • the power tool 20 takes a hand-held circular saw as an example, and mainly includes a bottom plate 21, a casing 22, a blade cover 23, a blade shaft 24, a motor 25, a motor shaft 251, a transmission 26, a battery pack 27, and a circuit.
  • the bottom plate 21 includes a bottom plate plane for contacting the workpiece, and the casing 22 is coupled to the bottom plate 21 and fixed above the plane of the bottom plate.
  • the saw blade is used as a functional part for implementing the cutting function
  • the saw blade shaft 24 is used as a tool attachment shaft for supporting the rotation of the saw blade in the saw blade cover 23 to realize the cutting work on the workpiece, the saw blade cover 23 is connected to the casing 22.
  • the motor 25 is disposed within the casing 22, and the motor 25 includes a stator, a rotor, and a multi-phase winding.
  • the motor shaft 231 is coupled to the rotor and driven by the rotor.
  • the motor 25 is operatively coupled to the saw blade by a transmission 26, in particular, the motor 25 is coupled to the motor shaft 251 and the blade shaft 24 via a transmission 26 to conduct rotational motion of the motor shaft 251 to the blade shaft 24, thereby Drive the saw blade to work.
  • the battery pack 27 is used as a power supply module for supplying power to the power tool 20.
  • the impact screwdriver 30 is similar to a pistol shape and mainly includes a casing 31 including a substantially cylindrical portion (not shown) disposed at an angle to the cylindrical portion.
  • the handle 32 is provided with an operation switch 34 for controlling the activation of the tool.
  • the intersection of the handle 32 and the cylindrical portion is further provided with a reversing button 35, which is respectively disposed on both sides of the casing 31 for controlling the forward and reverse of the tool.
  • the inside of the handle is further provided with a circuit board (not shown), and an electronic component or an electronic component such as a driving circuit and a controller is integrated on the circuit board.
  • the end of the casing 31 away from the handle 32 is the front end, and the other end is the rear end.
  • the motor 36, the transmission 37 driven by the motor, and the impact portion 38 are arranged in order from front to back.
  • the motor 17 has a motor shaft (not shown) that provides a rotational output, and a motor gear is provided at the top end of the motor shaft for transmitting the power rotary output of the motor 17 to the transmission 37 through the gear structure.
  • the transmission 37 is used to decelerate the rotational output of the motor shaft and then rotate the output.
  • a tool accessory shaft (not shown) is used to support the tool attachment that is coupled to the motor shaft by a transmission 37.
  • the operation of the above-described power tool (10, 20, 30) also depends on the circuitry.
  • the power tool 10 further includes a power module 41 , a controller 42 , and a drive circuit 43 .
  • FIG. 4 is merely illustrative and does not limit the content of the present disclosure.
  • the power module 41 is configured to supply power to the power tool 10.
  • the power module 41 includes a first power terminal 41a and a second power terminal 41b (FIG. 5).
  • the first power terminal 41a is specifically a power source of the power module 41.
  • the second power terminal 41b is specifically the negative terminal of the power supply module 41.
  • the power module 41 generates a potential difference between the first power terminal 41a and the second terminal 41b.
  • the power module 41 is electrically connectable to an external power source to provide power to the power tool 10.
  • the external power source can be an AC power source or a DC power source, for example, a battery pack.
  • the power module 41 can rectify, filter, divide, step down, etc. the AC signal output by the AC power through a hardware circuit.
  • the power module 41 can include DC-DC conversion circuit, etc.
  • the power tool 10 further includes a controller power module 47 electrically coupled to the power module 41 and the controller 42 for converting electrical energy from the power module 41 to the controller 42. The electrical energy used.
  • the controller 41 is electrically connected to the drive circuit 43 for outputting a drive signal to control the operation of the drive circuit 43.
  • controller 41 employs a dedicated control chip (e.g., MCU, Microcontroller 42, Microcontroller Unit).
  • the control chip internally includes a power driving unit (not shown) that utilizes the power driving unit to boost the driving capability of the output signal of the controller 41, and the power driving unit can also be implemented by an external power driving unit.
  • the drive circuit 43 is connected to the motor.
  • the motor (13, 25) may be a brushless motor 44 or a brushed motor, and the brushless motor 44 will be described below as an example to explain the solution of the present disclosure.
  • the brushless motor 44 includes a multi-phase winding.
  • the brushless motor 44 includes a first phase winding A, a second phase winding B, and a third phase winding C, and the drive circuit 43 is used to drive the motor 44 to operate.
  • the driving circuit 43 includes a first driving end 43a for electrically connecting with the first power terminal 41a of the power module 41, and a second driving terminal 43b for electrically connecting to the second power terminal 41b of the power module 41. connection.
  • the driving circuit 43 further includes a plurality of high-side switches, the high-side ends of the high-side switches are respectively electrically connected to the first driving end; the plurality of low-side switches, the low-side ends of the low-side switches are respectively electrically Connected to the second drive end.
  • the plurality of high-side switches are the switches Q1, Q3, and Q6 in FIG. 5, each of the high-side switches has a high side end and a low side end, and the high side switch Q1 has a high side end Q1H and a low side.
  • the high side terminal Q1H of the high side switch Q1, the high side terminal Q3H of the high side switch Q3, and the high side end Q5H of the high side switch Q5 are respectively connected to the first power supply terminal 41a of the drive circuit 43.
  • the plurality of low side switches are switches Q2, Q4 and Q6 in FIG. 5, and each of the low side switches also has a high side end and a low side end.
  • the low side switch Q2 has a high side terminal Q2H and a low side terminal Q2L
  • the low side switch Q4 has a high side end Q4H and a low side end Q4L
  • the low side switch Q5 has a high side end Q5H and a low side end Q5L.
  • the low side terminal Q2L of the low side switch Q2, the low side terminal Q4L of the low side switch Q4, and the low side terminal Q6L of the low side switch Q6 are respectively connected to the second power supply terminal 41b of the drive circuit 43.
  • the low side terminal Q1L of the high side switch Q1 is connected to the high side end Q2H of the low side switch Q3, and the low side end Q3L of the high side switch Q3 is connected to the high side end Q4H of the low side switch Q4, and the low side of the high side switch Q5 is connected.
  • the terminal Q5L is connected to the high side terminal Q6H of the low side switch Q6.
  • the ground side end Q1L of the high side switch Q1 and the high side end Q2H of the low side switch Q2 are both connected to the first phase winding A, the ground side end Q3L of the high side switch Q3 and the high side of the low side switch Q4.
  • the terminal Q4H is connected to the second phase winding B, and the ground side terminal Q5L of the high side switch Q51 and the high side terminal Q6H of the low side switch Q6 are both connected to the third phase winding C.
  • the three-phase windings A, B, and C of the brushless motor 44 are connected to the power supply module 41 via the bridges of the high-side switches Q1, Q3, and Q5 and the plurality of low-side switches Q2, Q4, and Q5.
  • the high side switch and the low side switch described above may be semiconductor devices such as metal-oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs).
  • MOSFETs metal-oxide semiconductor field effect transistors
  • IGBTs insulated gate bipolar transistors
  • Each of the high side switch Q1 and the low side switch has a parasitic diode in parallel.
  • AH, AL, BH, BL, CH, and CL are the control terminals of the high side switch Q1, the low side switch Q2, the high side switch Q3, the low side switch Q4, the high side switch Q5, and the low side switch Q6, respectively.
  • the control terminals AH, AL, BH, BL, CH, and CL of the switches Q1 to Q6 are electrically connected to the controller 42, respectively.
  • the control terminals of the switches are gates, and each of the switches Q1 to Q6 is drained.
  • the poles or sources are connected to the respective phase windings of the brushless motor 44.
  • the drains of the high side switches Q1, Q3, and Q5 can be connected to the first power terminal 41a of the power module 41 through the first driving end 43a, and the sources of the high side switches Q1, Q3, and Q5 are respectively connected to The first phase winding A, the second phase winding B, and the third phase winding C; the drains of the low side switches Q2, Q4, Q6 are respectively connected to the first phase winding A, the second phase winding B, and the third phase winding C, The sources of the low side switches Q2, Q4, and Q6 can be connected to the second power terminal 41b of the power module 41 through the second driving terminal 43b.
  • the switches Q1 to Q6 change the conduction state in accordance with the control signal output from the controller 42, thereby changing the voltage state of the power module 41 loaded on the winding of the brushless motor 11.
  • the high-side switches Q1, Q3, and Q5 are used to turn on or off the first phase winding A, the second phase winding B, the third phase winding C, and the first power terminal 41a of the power module 41, respectively.
  • the low-side switches Q2, Q4, and Q6 are used to electrically connect or disconnect the first phase winding A, the second phase winding B, and the third phase winding C to the second power terminal 41b of the power module 41, respectively.
  • the power tool 10 further includes a position detection module 45 coupled to the brushless motor 44 and the controller 42 for detecting the position of the rotor in the brushless motor 44. Specifically, when the rotor is rotated to a predetermined range, the position detecting module 45 is in a signal state, and the position detecting module 45 switches to another signal state when the rotor is rotated out of the preset range.
  • the position detection module 45 includes a position sensor 451 (eg, a Hall sensor). In other embodiments, the position detection module 45 does not include the position sensor 451, but instead determines the rotor position by a back electromotive force signal. phase.
  • the position detecting module includes a position sensor 451, and the position sensor 451 is three Hall sensors. As shown in FIG. 4, three Hall sensors are provided along the circumferential direction of the rotor of the brushless motor 44, and the position information of the rotor detected by the Hall sensor is input to the position detecting module 45.
  • the position detection module 45 converts the position of the input rotor to a controller 42 by logically processing the rotor position information communicable with the controller 42. When the rotor is turned in and out of the preset range, the signal of the Hall sensor changes, and the output signal of the position detecting module 45 also changes.
  • the output signal of the position detecting module 45 is defined as 1, and when the rotor is rotated out of the preset range, the output signal of the position detecting module 45 is defined as 0.
  • the three Hall sensors are at a physical angle of 120° from each other.
  • the three Hall sensors When the rotor is rotated, the three Hall sensors will generate a position signal comprising a combination of the six signals such that the position detecting module 45 outputs a position signal comprising one of the six signal combinations. If arranged in the order in which the Hall sensors are placed, six different signal combinations 100, 110, 010, 011, 001, 101 appear. In this way, the position detecting module 45 can output one of the six position signals, and the position of the rotor can be known according to the position detecting signal output by the position detecting module 45.
  • a brushless motor 44 having a three-phase winding it has six driving states corresponding to an output signal generated by the above-described scheme in one energization period, and therefore, when the output signal of the position detecting module 45 changes, the brushless motor 44 can perform a reversal.
  • the drive circuit 43 In order to rotate the brushless motor 44, the drive circuit 43 has a plurality of driving states. In one driving state, the stator winding of the brushless motor 44 generates a magnetic field, and the controller 42 controls the driving circuit 43 to switch the driving state to rotate the magnetic field generated by the winding.
  • the drive of the brushless motor 44 is achieved by driving the rotor to rotate.
  • the drive circuit 43 has at least six drive states.
  • the following terminals in the drive state correspondingly turned on indicate the drive state.
  • the controller 42 controls the drive circuit 43 to connect the first phase winding A to the first power terminal 41a of the power module 41 and the second phase winding B to the second power terminal 41b of the power module 41
  • the driving state Indicated by AB in this state, the first phase winding A and the second phase winding B are turned on, referred to as AB phase conduction
  • the controller 42 controls the drive circuit 43 to connect the first phase winding A to the power module 41
  • the second power supply terminal 41b and the second phase winding B are connected to the first power supply terminal 41b of the power supply module 41, and the driving state is indicated by BA, in which the first phase winding A and the second phase winding B are turned on.
  • the BA phase conduction It is called the BA phase conduction, and its current direction is opposite to that of AB.
  • the driving method thus indicated is also applicable to the triangular connection scheme of the winding. Further, the switching of the driving state may be simply referred to as the reversing operation of the brushless motor 44. Obviously, the brushless motor 44 is reversed every time the rotor rotates by 60 degrees, and the interval between the one commutation of the brushless motor 44 and the next commutation is defined as the commutation interval.
  • Fig. 6a is a waveform diagram of a first conventional control signal of the drive circuit 43.
  • the high side switches (Q1, Q3, Q5) on the current loop use pulse width modulated PWM signals to control motor speed. Specifically, during the PWM signal control of one of the high-side switches, one of the low-side switches maintains an on state, and the high-side switch, the low-side switch and the corresponding winding form a current loop on the current loop.
  • the power supply current of the power module 41 passes through the first driving end 43a, the high side switch, the winding, and the low side open tube.
  • the controller 42 to control the brushless motor 44 to make the motor driving state in the AB state as an example, the high-side switch Q1 is controlled by the PWM signal.
  • the controller 42 outputs a low-level signal to the low-side switch.
  • Q4 is kept in an on state, and the high side switch Q1 and the low side switch Q4 form a current loop with the corresponding first phase winding A and second phase winding B.
  • the power supply current of the power module 41 The first driving end 43a, the high side switch Q1, the first phase winding A, the second phase winding B, the low side open tube Q4, and the second driving end 43b pass through the first driving end 43a, as shown in Fig. 7a.
  • Figure 6b is a second conventional control signal waveform diagram.
  • the low side switches (Q2, Q4, Q6) on the current loop use pulse width modulated PWM signals to control motor speed. Specifically, during the PWM signal control period of one of the low-side switches, one of the high-side switches maintains an on state, and the high-side switch, the low-side switch and the corresponding winding form a current loop, and on the current loop, The power supply current of the power module 41 passes through the first driving end 43a, the high side switch, the winding, the low side switch, and the second driving end.
  • the low side switch Q4 is controlled by the PWM signal, and during the PWM signal control of the low side switch Q4, the controller 42 outputs a high level signal to the high side.
  • the switch Q1 is kept in an on state, and the high side switch Q1 and the low side switch Q4 form a current loop with the corresponding first phase winding A and second phase winding B.
  • the power supply of the power module 41 The current passes through the first driving end 43a, the high side switch Q1, the first phase winding A, the second phase winding B, the low side open tube Q4, and the second drive end 43b.
  • the brushless motor 44 is reversed every time the rotor is rotated by 60 degrees, that is, the motor drive state is switched from the previous state to the next state every time the rotor is rotated by 60 degrees. Referring to FIG. 6a, FIG. 7a and FIG.
  • the process of controlling the motor driving state of the brushless motor 44 from the AB state to the AC state by the controller 42 is taken as an example, wherein the high side switch PWM signal control mode is adopted: the controller 42 output PWM signal to the control terminal AH of the high side switch Q1 to turn on or off the high side switch Q1, the controller 42 synchronously outputs a high level signal to the control terminal BL of the low side switch Q4 to keep the low side switch Q4 turned on. State, the first phase winding A and the second phase winding B are energized, the motor driving state is in the AB state (as shown in FIG.
  • the controller 42 outputs a PWM signal to the control terminal AH of the high side switch Q1 to turn on the high side switch Q1 or Turning off, the controller 42 synchronously outputs a low level signal to the control terminal BL of the low side switch Q4 to keep the low side switch Q4 in the off state, and the controller 42 synchronously outputs a high level signal to the control terminal CL of the low side switch Q6.
  • the low side switch Q6 remains in the on state, the motor drive state is switched from the AB state to the AC state, the first phase winding A and the third phase winding C are energized, and the second phase winding B is de-energized (Fig. 7b).
  • each switch has a parasitic diode in parallel, during the PWM signal control of one of the high-side switches, when it is switched from the on state to the off state, due to the presence of inductive components in the loop (for example, the winding of the motor) The current cannot be transient and the motor current will pass through the parasitic diode of the low side switch connected to the low side of the high side switch.
  • FIG. 7a when the motor driving state is in the AB state, the high side switch Q1 is turned on and the low side switch Q4 is turned on.
  • the motor driving state is switched from the AB state of FIG. 7a to the AC state of FIG. 7b, as shown in FIG. As shown in Fig.
  • the controller 42 of the power tool 10 of the present disclosure is configured to output a first control signal to the high side switch (Q1, Q3, Q5) One of the high side switches (Q1, Q3, Q5) is in an on state or an off state; outputting a second control signal to one of the low side switches (Q2, Q4, Q6) to enable One of the low side switches (Q2, Q4, Q6) is in the other of the on and off states; wherein the low side of one of the high side switches (Q1, Q3, Q5) is connected to the low side The high side of one of the side switches (Q2, Q4, Q6) to reduce heat and loss.
  • the first control signal causes one of the high side switches to be in an off state
  • the second control signal causes the low side switch directly connected to the low side end of the high side switch to be in a conducting state.
  • the pass state, and/or the second control signal causes one of the low side switches to be in an off state during the off state, the first control signal causing the high side switch directly coupled to the high side end of the low side switch to be in an on state.
  • the high side switch and the low side switch to which the low side end of the high side switch and the high side end of the low side switch are directly connected have opposite on and off states.
  • the low side switch does not pass through the parasitic diode to reduce heat and power loss.
  • first control signal output by the controller 42 is a first PWM signal; and the second control signal output by the controller is a second PWM signal.
  • the controller synchronously outputs the first control signal and the second control signal.
  • the high-side switch adopts a PWM control mode
  • the controller 42 is configured to: output a first control signal to enable one of the high-side switches to be in an on state or an off state, and the first control signal is a PWM signal; outputting a high level signal such that one of the low side switches remains in an on state during the PWM signal control of the high side switch to form a current loop; synchronizing the output of the second control signal to the high side switch
  • the low side switch connected to the low side end is in the other of the on and off states, and the second control signal is the second PWM signal.
  • the controller 42 outputs a first control signal to turn the high-side switch Q1 into an on state or an off state
  • the first control signal is a first PWM signal
  • the controller 42 outputs a high level signal.
  • the controller 42 synchronously outputs the second control signal to make the low side connected to the low side end of the high side switch Q1.
  • the switch Q2 is in the other of the on and off states, and the second control signal is a PWM signal.
  • the low side switch adopts a PWM signal control mode
  • the controller 42 is configured to: output a second control signal to enable one of the low side switches to be in an on state or an off state, and the second control signal is a second PWM signal; outputting a high level signal to cause one of the high side switches to remain in an on state during PWM signal control of the low side switch to constitute a current loop; synchronizing outputting the first control signal to be high with the low side switch
  • the side-connected high-side switch is in the other of the on and off states, and the first control signal is the first PWM signal.
  • the controller 42 outputs a second control signal to make the low side switch Q4 in an on state or an off state, the second control signal is a second PWM signal; and the controller 42 outputs a high level signal.
  • Q1 is kept in the high side switch during the PWM signal control of the low side switch Q4 to constitute a current loop; the controller synchronously outputs the first control signal to enable the high side switch Q3 connected to the high side end of the low side switch Q4.
  • the first control signal is the first PWM signal.
  • the controller 42 synchronously outputs the second PWM signal only when the duty ratio of the first PWM signal satisfies a preset condition. Specifically, the controller 42 outputs the second PWM signal when the duty ratio of the first PWM signal is within a preset range.
  • the controller 42 outputs the second PWM signal when at least the duty ratio of the first PWM signal is in the range of 20% to 90% (including 20% and 90%).
  • the controller 42 when at least the duty ratio of the first PWM signal is in the range of 10% to 95% (including 10% and 95%), the controller 42 outputs the second PWM signal to control the low side switch of the phase bridge circuit.
  • the controller 42 when at least the duty ratio of the first PWM signal is in the range of 30% to 95% (including 30% and 95%), the controller 42 outputs the second PWM signal to control the low side switch of the phase bridge circuit.
  • the controller 42 outputs the second PWM signal only when the first PWM signal satisfies the preset condition.
  • the advantage of this is that, on the one hand, when the first PWM signal output by the controller 42 causes one of the high side switches to be in an off state, the second PWM signal output by the controller 42 is made to be the low side of the high side switch. The connected low-side switch is in an on state. If the duty of the first PWM signal is small, the current of the corresponding winding drops rapidly, and the current is less than zero. The current less than zero generates a negative torque and causes a braking effect.
  • the second PWM signal output by the controller 42 causes Low side of the high side switch
  • the low side switch of the terminal connection is in an on state. If the duty ratio of the first PWM signal is large, the above scheme may make the duty ratio of the second PWM signal to be inserted small, and the effect thereof is not large, but instead Switching losses are caused by frequent switching of the switches.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset time length T1, and a rising edge of the first control signal and the first
  • the falling edges of the two control signals are separated by a second predetermined duration T2. That is, the first preset duration T1 is the time interval between the falling edge of the first control signal and the rising edge of the second control signal, and the second preset duration T2 is the rising edge and the second of the first control signal. The time interval between the falling edges of the control signal.
  • the advantage of this is that, on the one hand, it can avoid starting the rising edge of the second control signal immediately when the first control signal is at the falling edge, and the low-side switch is already turned on when the high-side switch is not completely disconnected. Short-circuit phenomenon, which causes the burning of circuits and electronic components. Specifically, referring to FIG. 12a, the actual square wave signal is not a square wave signal in a strict sense due to the influence of the rise/fall time, and the rising edge and the falling edge cannot be transient, but a small delay time T is slow. Variety. Referring to FIG.
  • the second control signal output by the controller 42 is connected to the low side end of the high side switch Q1.
  • the low side switch Q2 is turned on. If the rising edge of the second control signal is started immediately when the first control signal is at the falling edge, the high side switch Q1 and the low side switch Q2 are simultaneously turned on. A short circuit occurs, which may cause damage or even burnt of electronic components.
  • the first preset duration T1 is separated between the falling edge of the first control signal and the rising edge of the second control signal, so that the short circuit phenomenon can be effectively avoided.
  • the duty ratio of the second PWM signal may alternatively be in the range of 20% to 90%.
  • the duty ratio of the second PWM signal ranges from 10% to 95%.
  • the duty ratio of the second PWM signal ranges from 30% to 95%.
  • the negative torque generation can be effectively avoided and the motor speed can be decreased.
  • the first control signal output by the controller 42 is applied to the control terminal AH terminal of the high-side switch Q1
  • the second control signal output by the controller 42 is applied to the high-side switch Q1.
  • the control terminal AL end of the low side switch Q2 connected to the low side end waits for the first preset time period T1 to start the rising edge of the second control signal after the start of each falling edge of the first control signal, and in the second control After the falling edge of the signal starts, it waits for the second preset time period T2 to start the rising edge of the first control signal.
  • the first control signal is a first PWM signal
  • the second control signal is a second PWM signal.
  • the phenomenon that the high-side switch Q1 and the low-side switch Q2 are simultaneously turned on does not occur, so that the short-circuit phenomenon can be avoided, and because the second preset duration T2 In the case of light load, it is possible to avoid the occurrence of negative torque and the braking effect causes the motor speed to decrease.
  • the first preset duration T1 ranges from 0.5 microseconds to 10 microseconds (including the endpoints of 0.5 microseconds and 10 microseconds).
  • the second preset duration ranges from 5 microseconds to 30 microseconds.
  • the actual experimental results show that when the first preset time length T1 is between 0.5 microseconds and 10 microseconds (including the end points of 0.5 microseconds and 10 microseconds), the short circuit problem can be prevented, and the temperature rise effect is suppressed.
  • first preset time length T1 to avoid the high side switch and the low side of the high side switch
  • the low side switch of the end connection is simultaneously turned on to cause a short circuit.
  • second predetermined time length T2 to avoid generating a negative torque to cause a braking effect.
  • the sum of the duty ratio of the first PWM signal and the duty ratio of the second PWM signal is set to be less than 100% to avoid the high side switch and the low side switch connected to the low side end of the high side switch simultaneously Turning on causes a short circuit to occur, and/or avoids a negative torque that causes the braking effect to cause the motor speed to drop.
  • the current corresponding to the on winding increases. Conversely, when the high side switch is in the off state and the low side switch connected to the low side end of the high side switch is in the on state, the current corresponding to the on winding is decreased.
  • the ratio of the first preset duration T1 and the second preset duration T2 is set to be less than or equal to 1.
  • the first preset duration T1 is set to 0.5 microseconds
  • the second preset duration T2 is set to 0.8 microseconds; for example, the first preset duration T1 is set to 1 microsecond, and the second preset is set.
  • the duration T2 is set to 2 microseconds; for example, the first preset duration T1 is set to 10 microseconds, and the second preset duration is set to 13 microseconds.
  • the current of the motor winding is greater than or equal to zero. In this way, the motor does not output negative torque and the braking effect is generated when the motor is driven, resulting in a decrease in the motor speed.
  • power tool 10 further includes a current measurement module 46 (Fig. 4) for detecting or estimating phase current.
  • the controller 42 is configured to: when the phase current is less than or equal to zero, the controller 42 outputs a second control signal to turn off one of the low side switches So that the motor maintains a positive output torque, one of the low side switches being a low side switch connected to the low side end of the currently conducting high side switch.
  • the controller 42 is configured to: when the phase current is less than or equal to zero, the controller 42 outputs a first control signal to turn off one of the high side switches In order for the motor to maintain a positive output torque, one of the high side switches is a high side switch connected to the high side end of the currently conducting low side switch.
  • an NTC temperature sensor for temperature sampling is generally disposed on a circuit board near a position of at least one switch of the driving circuit to effectively monitor the temperature of the bridge switch to prevent the temperature from being too high to damage the electronic component.
  • a temperature sensor not only increases board design and component costs, but also increases board size.
  • the controller 42 of the present disclosure employs an MCU integrated with a temperature sensor internally, and uses the temperature sensor instead of the additional temperature sampling NTC temperature sensor to estimate the temperature of the switch of the driving circuit 43. And when the temperature detection value of the drive circuit 43 exceeds the preset threshold, the controller 42 controls the drive circuit 43 to stop operating.
  • the temperature sensor integrated in the controller 42 is used to measure the temperature of the driving circuit 43, which simplifies the circuit board design, saves component costs, and makes the board size more compact. In some specific embodiments, the sum of the single-sided areas of all of the boards is less than 2,500 cm ⁇ 2.
  • a single-chip microcomputer is integrated with a temperature sensor integrated therein, which can be used to measure the ambient temperature of the CPU, and the measured result can be used to estimate the temperature of the driving circuit 43 when the detected temperature exceeds a preset value.
  • the temperature protection function is turned on, for example, turning off the power tool, turning on the heat dissipation fan, turning off the drive circuit 43, and the like.
  • the above embodiment is a power tool 10 having a brushless motor 44 having three-phase windings. It will be understood by those skilled in the art that the above technical solution can also be applied to other power tools having a brushless motor 44, such as two phases. Brushless Motor.
  • the present disclosure also discloses a control method for a power tool, the power tool comprising: a driving circuit, comprising: a first driving end electrically connected to the first power terminal; a second driving end, and the second The power supply end is electrically connected; the high side switch includes a high side end and a low side end, and the high side end of the high side switch is electrically connected to the first driving end respectively; the plurality of low side a switch, the low side switch includes a high side end and a low voltage end, the low side end being electrically connected to the second driving end respectively; the control method of the power tool comprises: one of the high side switches In an on state or an off state; causing one of the low side switches to be in another of an on state and an off state; wherein a low side end of one of the high side switches is coupled to the low side
  • the high side of one of the switches is such that a non-transient current passes through the low side switch without passing through the parasitic diode in parallel with the low side switch to reduce heat generation and
  • the first control signal is a first PWM signal; and the second control signal is a second PWM signal.
  • the controller outputs the second control signal when the first control signal meets the preset condition.
  • the duty ratio of the first PWM signal ranges from 20% to 90%.
  • the duty ratio of the first PWM signal ranges from 10% to 95%.
  • the duty ratio of the first PWM signal ranges from 30% to 95%.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset time length T1.
  • the first preset duration T1 ranges from 5 microseconds to 10 microseconds, and includes an endpoint to prevent short circuit problems while suppressing a better temperature rise effect.
  • a rising edge of the first control signal is spaced apart from a falling edge of the second control signal by a second predetermined duration T2.
  • a falling edge of the first control signal is spaced apart from a rising edge of the second control signal by a first preset time length T1, and a rising edge of the first control signal and the second control
  • the falling edges of the signals are separated by a second predetermined duration T2.
  • the ratio of the first preset duration T1 to the second preset duration T2 is less than or equal to 1. This has the advantage that it is possible to further avoid the generation of a negative torque and cause a braking effect to cause the motor speed to drop.
  • the sum of the duty ratio of the first PWM signal and the duty ratio of the second PWM signal is less than 100%.
  • control method of the power tool further includes: when the phase current is less than or equal to zero, outputting a second control signal to turn off one of the low side switches such that the motor maintains output forward torque.
  • One of the low side switches is a low side switch connected to the low side end of the currently conducting high side switch.
  • the above embodiment is an example in which the high side switch adopts a PWM control method.
  • the control method thereof is similar to the above embodiment, and details are not described herein again.
  • the duty ratio of the second PWM signal is optionally in the range of 20% to 90%.
  • the duty ratio of the second PWM signal ranges from 10% to 95%.
  • the duty ratio of the second PWM signal ranges from 30% to 95%.
  • the present disclosure provides a power tool and a control method capable of effectively suppressing temperature rise of a drive circuit and reducing power loss.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Inverter Devices (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

一种电动工具以及控制方法，电动工具包括功能件（12）、电机（13）、电源模块（41）、驱动电路（43）以及控制器（42），驱动电路（43）包括：第一驱动端（43a）和第二驱动端（43b），分别与电源模块（41）的第一电源端（41a）和第二电源端（41b）电性连接；多个高侧开关（Q1、Q3、Q5），高侧开关的高侧端分别电性连接至第一驱动端（43a）；多个低侧开关（Q2、Q4、Q6），低侧开关的低侧端分别电性连接至第二驱动端（43b）；控制器（42）被配置为：输出第一控制信号至高侧开关中的一个以使高侧开关中的一个处于导通状态或关断状态；输出第二控制信号至低侧开关中的一个以使低侧开关中的一个处于导通和关断状态中的另一个；其中，高侧开关中的一个的低侧端连接至低侧开关中的一个的高侧端。该电动工具能够有效抑制驱动电路温升，降低功率损耗。

Description

电动工具及其控制方法 技术领域
本公开涉及一种电动工具及其控制方法，具体涉及一种能够抑制开关温升及功率损耗的电动工具及其控制方法。
背景技术
电动工具通常通过电机驱动功能件运动，从而实现电动工具的功能。电机可以是无刷电机，也可以是有刷电机。对于无刷电机而言，其驱动电路通常采用逆变驱动桥电路进行控制，逆变驱动桥电路的功率元件也即开关(MOSFET、IGBT等)通常会产生大量的热量。由于开关存在寄生二极管，在该开关从接通状态切换到断开状态时，由于电流不能瞬变，电机绕组中的电流会通过另一开关的寄生二极管，寄生二极管因内部电阻而发热，使得该寄生二极管的开关以及驱动电路温度上升。尤其是，在重载大电流状态下，其发热损耗更为严重。
发明内容
为解决现有技术的不足，本公开的目的在于提供一种能够抑制开关温升以及功率损耗的电动工具及其控制方法。
为了实现上述目标，本公开采用如下的技术方案：
一种电动工具，包括：功能件，用于实现所述电动工具的功能；电机，用于驱动所述功能件，所述电机包括多个绕组；电源模块，用于提供供电电流，包括第一电源端和第二电源端；驱动电路，电连接至所述电机，所述驱动电路包括：第一驱动端，与所述第一电源端电性连接；第二驱动端，与所述第二电源端电性连接；多个高侧开关，所述高侧开关的高侧端分别电性连接至所述第一驱动端；多个低侧开关，所述低侧开关的低侧端分别电性连接至所述第二驱动端；控制器，被配置为：输出第一控制信号至所述高侧开关中的一个以使所述高侧开关中的一个处于导通状态或关断状态；输出第二控制信号至所述低侧开关中的一个以使所述低侧开关中的一个处于导通和关断状态中的另一个；其中，所述高侧开关中的一个的低侧端连接至所述低侧开关中的一个的高侧端。
可选地，所述控制器输出的第一控制信号为第一PWM信号；所述控制器输出的第二控制信号为第二PWM信号。
可选地，所述第一PWM信号的占空比的取值范围为20％～90％。
可选地，所述第一PWM信号的占空比的取值范围为10％～95％。
可选地，所述第一PWM信号的占空比的取值范围为30％～95％。
可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长。
可选地，所述第一预设时长的取值范围为5微秒～10微秒。
可选地，所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
可选地，所述第二预设时长的取值范围为5微秒～30微秒。
可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
可选地，所述第一预设时长与所述第二预设时长的比值小于等于1。
可选地，所述控制器同步输出所述第一控制信号和所述第二控制信号。
可选地，所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。
可选地，所述第二PWM信号的占空比的取值范围为20％～90％。
可选地，所述第二PWM信号的占空比的取值范围为10％～95％。
可选地，所述第二PWM信号的占空比的取值范围为30％～95％。
可选地，所述电动工具还包括：电流测算模块，用于检测或估算相电流；所述控制器被配置为：在所述相电流小于等于零时，所述控制器被配置为在所述相电流小于等于零时，所述控制器被配置为输出第二控制信号以关断所述低侧开关中的一个，或输出第一控制信号控制以关断与所述高侧开关中的一个。
所述控制器包括设置于所述控制器内部的温度传感器，所述控制器根据所 述温度传感器的检测值估算所述驱动电路的温度，并且在所述驱动电路的温度检测值超过预设阈值时，所述控制器控制驱动电路停止工作。
另一种电动工具，包括：功能件，用于实现所述电动工具的功能；电机，用于驱动所述功能件，所述电机包括多个绕组；电源模块，用于提供供电电流，包括第一电源端和第二电源端；驱动电路，电连接至所述电机，包括：第一驱动端，与所述第一电源端电性连接；第二驱动端，与所述第二电源端电性连接；第一高侧开关，所述第一高侧开关的高侧端电性连接至所述第一驱动端；第一低侧开关，所述第一低侧开关的低侧端电性连接至所述第二驱动端；控制器，被配置为：输出第一控制信号至所述第一高侧开关以使所述第一高侧开关处于导通状态或关断状态；输出第二控制信号至所述第一低侧开关以使所述第一低侧开关处于导通或关断状态中的另一个；其中，所述第一高侧开关的低侧端连接至所述第一低侧开关的高侧端。
可选地，所述驱动电路还包括第二低侧开关，所述第二低侧开关的低侧端电性连接至所述第二驱动端；所述控制器被配置为：输出所述第一控制信号至所述第一高侧开关和所述第二低侧开关以构成第一电流回路；在所述第一电流回路中，所述电源模块提供的供电电流依次经所述第一驱动端、第一高侧开关、绕组、第二低侧开关和第二驱动端。
可选地，所述控制器输出的第一控制信号为第一PWM信号；所述控制器输出的第二控制信号为第二PWM信号。
可选地，所述第一PWM信号的占空比的取值范围为20％～90％。
可选地，所述第一PWM信号的占空比的取值范围为10％～95％。
可选地，所述第一PWM信号的占空比的取值范围为30％～95％。
可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长。
可选地，所述第一预设时长的取值范围为5微秒～10微秒。
可选地，所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间 隔第一预设时长，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
可选地，所述第一预设时长与所述第二预设时长的比值小于等于1。
可选地，所述控制器同步输出所述第一控制信号和所述第二控制信号。
可选地，所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。
可选地，所述第二PWM信号的占空比的取值范围为20％～90％。
可选地，所述第二PWM信号的占空比的取值范围为10％～95％。
可选地，所述第二PWM信号的占空比的取值范围为30％～95％。
可选地，所述电动工具还包括：电流测算模块，用于检测或估算相电流；所述控制器被配置为：在所述相电流小于等于零时，所述控制器被配置为在所述相电流小于等于零时，所述控制器被配置为输出第二控制信号以关断所述低侧开关中的一个，或输出第一控制信号控制以关断与所述高侧开关中的一个。。
一种电动工具的控制方法，所述电动工具包括：驱动电路，包括：第一驱动端，与所述第一电源端电性连接；第二驱动端，与所述第二电源端电性连接；多个高侧开关，所述高侧开关包括高侧端和低压端，所述高侧开关的高侧端分别电性连接至所述第一驱动端；多个低侧开关，所述低侧开关包括高侧端和低压端，所述低侧端分别电性连接至所述第二驱动端；所述电动工具的控制方法包括：使所述高侧开关中的一个处于导通状态或关断状态；使所述低侧开关中的一个处于导通和关断状态中的另一个；其中，所述高侧开关中的一个的低侧端连接至所述低侧开关中的一个的高侧端。
可选地，所述第一控制信号为第一PWM信号；所述第二控制信号为第二PWM信号。
可选地，所述第一PWM信号的占空比的取值范围为20％～90％。
可选地，所述第一PWM信号的占空比的取值范围为10％～95％。
可选地，所述第一PWM信号的占空比的取值范围为30％～95％。
可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间 隔第一预设时长。
可选地，所述第一预设时长的取值范围为5微秒～10微秒。
可选地，所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
可选地，所述第一预设时长与所述第二预设时长的比值小于等于1。
可选地，所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。
可选地，所述第二PWM信号的占空比的取值范围为20％～90％。
可选地，所述第二PWM信号的占空比的取值范围为10％～95％。
可选地，所述第二PWM信号的占空比的取值范围为30％～95％。
可选地，在所述相电流小于等于零时，第二控制信号使所述低侧开关中的一个关断，或所述第一控制信号使所述高侧开关中的一个关断。
本公开的有益之处在于能够抑制驱动电路和开关温升，降低功率损耗。
附图说明
图1是一种实施方式的电动工具的立体图；
图2是另一种实施方式的电动工具的立体图；
图3是另一种实施方式的电动工具的立体图；
图4是一种实施方式的电动工具的电路系统图；
图5是图4中驱动电路的简化图；
图6a是一种传统的驱动电路的控制信号的波形图；
图6b是另一种传统的驱动电路的控制信号的波形图；
图7a是电机驱动状态处于AB状态时的电流走向标示图；
图7b是电机驱动状态处于AC状态时的电流走向标示图；
图8是电机驱动状态从AB状态切换到AC状态时不能瞬变的电流走向标示图；
图9是本公开的控制器施加至各个开关的控制端的控制信号的波形图；
图10是一种实施方式的第一控制信号和第二控制信号的波形图；
图11是另一种实施方式的第一控制信号的波形图以及第二控制信号的波形图；
图12a是传统的施加于高侧开关Q1的控制端AH的控制信号的实际波形图和施加于低侧开关Q2的控制端AL的控制信号的实际波形图；
图12b是图12a中的传统的控制信号引起短路现象的电流走向标示图；
图13a是重载时绕组的电流I1以及轻载时绕组的电流I2的波形图；
图13b一种实施方式的施加于高侧开关Q1的控制端AH的第一控制信号和施加于低侧开关Q2的控制端AL的第二控制信号与电机输出扭矩的关系图；
图13c是另一种实施方式的施加于高侧开关Q1的控制端AH和施加于低侧开关Q2的控制端AL的控制信号与电机输出扭矩的关系图。
具体实施方式
以下结合附图和具体实施例对本公开作具体的介绍。
本公开的电动工具可以为手持式电动工具、花园类工具、花园类车辆如车辆型割草机，在此并非有所限制。本公开的电动工具10包括但不限于以下内容：螺丝批、电钻、扳手、角磨等需要调速的电动工具，砂光机等可能用来打磨工件的电动工具，往复锯、圆锯、曲线锯等可能用来切割工件；电锤等可能用来做冲击使用的电动工具。这些工具也可能是园林类工具，比如修枝机、链锯、车辆型割草机；另外这些工具也可能作为其它用途，比如搅拌机。只要这些电动工具10能够采用以下披露的技术方案的实质内容即可落在本公开的保护范围内。
参照图1，电动工具10包括但不限于：壳体11、功能件12、电机13。
壳体11构成电动工具10的主体部分，用于容纳电机13。壳体11的一端还用于安装功能件12。
功能件12用于实现电动工具10的功能，例如打磨、切削等。图1所示的电动工具10以手持式电钻为例，功能件12为钻头。功能件12可操作地与电机13连接，例如，通过工具附件轴与电机13连接。
电机13，用于驱动功能件12，从而带动功能件12工作，为功能件12提供动力。具体而言，电机13包括电机轴、转子、定子和多相绕组(图4和图5)，电机轴可操作地与功能件12连接，例如，通过传动装置14电机轴以及支撑功能件的工具附件轴，将电机轴的驱动力传递至工具附件轴，从而安装在工具附件轴上的功能件12工作。
参照图2，电动工具20以手持式圆锯为例，主要包括底板21、机壳22、锯片罩23、锯片轴24、电机25、电机轴251、传动装置26、电池包27、电路板28以及设置在电路板28上的电子元器件或电子部件。
底板21包括用于与工件接触的底板平面，机壳22与底板21连接并固定于底板平面上方。对于圆锯而言，锯片作为功能件，用于实现切割功能，锯片轴24作为工具附件轴，用于在锯片罩23内支持锯片转动从而实现对工件进行切割作业，锯片罩23与机壳22连接。
电机25设置于机壳22内，电机25包括定子、转子和多相绕组，电机轴231与由转子连接，由转子驱动。电机25可通过传动装置26可操作的连接锯片，具体地，电机25通过传动装置26连接电机轴251与锯片轴24，将电机轴251的旋转运动传导至所述锯片轴24，从而带动锯片运转。其中，电池包27作为供电模块用于为电动工具20提供电能。
参照图3，冲击螺丝批30类似于手枪形，主要包括：包括机壳31，机壳31包括一个基本上呈圆筒形的部分(未示出)，与该圆筒形部分成一定角度布置的把手32，以及设置于把手内部的电池33，电池33作为电源模块用于为冲击螺丝批30提供电能。把手32上设有用于控制工具启动的操作开关34，把手32和圆筒形部分的交接部分还设有换向钮35，其分别设于机壳31的两侧用于控制工具的正反转，把手内部还设有电路板(未示出)，电路板上集成有驱动电路、控制器等电子元器件或电子部件。以机壳31上远离把手32所在的一端为前端， 相对的另一端为后端，从前到后依次布置有电机36、由电机驱动的传动装置37以及冲击部分38。电机17具有一个提供旋转输出的电机轴(未示出)，电机轴的顶端设有电机齿轮，用于通过齿轮结构将电机17的动力旋转输出传递给传动装置37。传动装置37用于将电机轴的旋转输出减速后旋转输出。工具附件轴(未示出)用于支持工具附件，其通过传动装置37连接电机轴。
上述电动工具(10、20、30)的运行还依赖于电路系统。参照图4，作为一种实施方式的电动工具的电路系统40，以电动工具10为例，电动工具10还包括：电源模块41、控制器42、驱动电路43。图4仅是示例性说明，并不限制本公开的内容。
电源模块41用于为电动工具10提供电能，电源模块41包括第一电源端41a和第二电源端41b(图5)，作为可选地，第一电源端41a具体为电源模块41的电源正极端，第二电源端41b具体为电源模块41的电源负极端，电源模块41使得电第一电源端41a和第二电源端41b之间产生电势差。电源模块41能够与外部电源实现电连接，从而为电动工具10提供电能。外部电源可以是交流电源，也可以是直流电源，例如，电池包。在一些实施实施方式中，对于交流电源而言，电源模块41可以通过硬件电路对交流电源输出的交流信号进行整流、滤波、分压、降压等，对于直流电源而言，电源模块41可以包括DC-DC转换电路等。
在一些实施例中，电动工具10还包括控制器电源模块47，其与电源模块41和控制器42电性连接，控制器电源模块47用于将来自电源模块41的电能转换成供控制器42使用的电能。
控制器41电连接至驱动电路43，用以输出驱动信号控制所述驱动电路43工作。在一些实施例中，控制器41采用专用的控制芯片(例如，MCU，微控制器42，Microcontroller Unit)。控制芯片内部包括功率驱动单元(未示出)，利用功率驱动单元提升控制器41输出信号的驱动能力，所述功率驱动单元也可采用外置式的功率驱动单元实现。
驱动电路43与电机连接。电机(13、25)可以是无刷电机44，也可以是有刷电机，下面以无刷电机44为例说明本公开的方案。
无刷电机44包括多相绕组，作为可选地，无刷电机44包括第一相绕组A、第二相绕组B和第三相绕组C，驱动电路43用于驱动电机44工作。驱动电路 43包括：第一驱动端43a，第一驱动端43a用于与电源模块41的第一电源端41a电连接；第二驱动端43b，用于与电源模块41的第二电源端41b电连接。驱动电路43还包括多个高侧开关，所述高侧开关的高侧端分别电性连接至所述第一驱动端；多个低侧开关，所述低侧开关的低侧端分别电性连接至所述第二驱动端。
作为可选地，所述的多个高侧开关为图5中的开关Q1、Q3、Q6，各个高侧开关均具有高侧端和低侧端，高侧开关Q1具有高侧端Q1H和低侧端Q1L，高侧开关Q3具有高侧端Q3H和低侧端Q3L，高侧开关Q5具有高侧端Q5H和低侧端Q5L。高侧开关Q1的高侧端Q1H、高侧开关Q3的高侧端Q3H、高侧开关Q5的高侧端Q5H均分别连接至驱动电路43的第一电源端41a。
作为可选地，所述的多个低侧开关为图5中的开关Q2、Q4和Q6，各个低侧开关也均具有高侧端和低侧端。低侧开关Q2具有高侧端Q2H和低侧端Q2L，低侧开关Q4具有高侧端Q4H和低侧端Q4L，低侧开关Q5具有高侧端Q5H和低侧端Q5L。低侧开关Q2的低侧端Q2L、低侧开关Q4的低侧端Q4L、低侧开关Q6的低侧端Q6L均分别连接至驱动电路43的第二电源端41b。
上述高侧开关Q1的低侧端Q1L与低侧开关Q3的高侧端Q2H连接，高侧开关Q3的低侧端Q3L与低侧开关Q4的高侧端Q4H连接，高侧开关Q5的低侧端Q5L与低侧开关Q6的高侧端Q6H连接。
作为可选地，高侧开关Q1的地侧端Q1L和低侧开关Q2的高侧端Q2H均连接至第一相绕组A，高侧开关Q3的地侧端Q3L和低侧开关Q4的高侧端Q4H均连接至第二相绕组B，高侧开关Q51的地侧端Q5L和低侧开关Q6的高侧端Q6H均连接至第三相绕组C。无刷电机44的三相绕组A、B、C通过上述高侧开关Q1、Q3、Q5和多个低侧开关Q2、Q4、Q5组成的电桥与电源模块41相连接。上述高侧开关和低侧开关可以是半导体器件，例如，金属-氧化物半导体场效应晶体管(MOSFET)或者绝缘栅双极型晶体管(IGBT)。每个高侧开关Q1和低侧开关均并联有一个寄生二极管。AH、AL、BH、BL、CH、CL分别为高侧开关Q1、低侧开关Q2、高侧开关Q3、低侧开关Q4、高侧开关Q5、低侧开关Q6的控制端。
下面以MOSFET作为开关为例，具体说明驱动电路43的构成。开关Q1～Q6 的控制端AH、AL、BH、BL、CH、CL与分别于控制器42电性连接，对于MOSFET而言，各个开关的控制端为栅极，开关Q1～Q6的每个漏极或源极与无刷电机44的各相绕组连接。作为可选地，高侧开关Q1、Q3、Q5的漏极均能通过第一驱动端43a连接至电源模块41的第一电源端41a，高侧开关Q1、Q3、Q5的源极分别连接至第一相绕组A、第二相绕组B、第三相绕组C；低侧开关Q2、Q4、Q6的漏极分别连接至第一相绕组A、第二相绕组B、第三相绕组C，低侧开关Q2、Q4、Q6的源极均能通过第二驱动端43b连接至电源模块41的第二电源端41b。开关Q1～Q6依据控制器42输出的控制信号改变导通状态，从而改变电源模块41加载在无刷电机11的绕组上的电压状态。在本实施方式中，高侧开关Q1、Q3、Q5分别用于导通或切断第一相绕组A、第二相绕组B、第三相绕组C与电源模块41的第一电源端41a的电性连接，低侧开关Q2、Q4、Q6分别用于导通或切断第一相绕组A、第二相绕组B、第三相绕组C与电源模块41的第二电源端41b的电性连接。
作为可选地，电动工具10还包括位置检测模块45，其与无刷电机44和控制器42连接，用于检测无刷电机44中的转子的位置。具体地，当转子转动至一个预设范围时，位置检测模块45处于一种信号状态，当转子转出预设范围时位置检测模块45切换至另一信号状态。在一些实施例中，位置检测模块45包括位置传感器451(例如，霍尔传感器)，在另一些实施例中，位置检测模块45不包括位置传感器451，而是通过反电动势信号判断转子位置进行换相。
在本实施例中，位置检测模块包括位置传感器451，所述的位置传感器451为三个霍尔传感器。如图4所示，沿无刷电机44的转子的圆周方向设置3个霍尔传感器，霍尔传感器检测的转子的位置信息输入至位置检测模块45。位置检测模块45将输入的转子的位置经逻辑处理转换为可与控制器42通讯的转子位置信息输入至控制器42。当转子转入和转出预设范围时，霍尔传感器的信号发生改变，位置检测模块45的输出信号也随之改变。
转子转入预设范围时，位置检测模块45的输出信号定义为1，而转子转出预设范围时，位置检测模块45的输出信号定义为0。将三个霍尔传感器彼此相距物理角度120°。
当转子转动时，三个霍尔传感器将会产生包括六种信号组合的位置信号使 得位置检测模块45输出包括六种信号组合之一的位置信号。如果按霍尔传感器放置的顺序排列则出现六个不同的信号组合100、110、010、011、001、101。这样一来位置检测模块45就可输出上述六个位置信号之一，依据位置检测模块45输出的位置检测信号即可得知转子所处的位置。
对于具有三相绕组的无刷电机44而言，其在一个通电周期内具有六个驱动状态与上述方案产生的输出信号相对应，因此在位置检测模块45的输出信号发生变化时，无刷电机44即可执行一次换向。
为了使无刷电机44转动，驱动电路43具有多个驱动状态，在一个驱动状态下无刷电机44的定子绕组会产生一个磁场，控制器42控制驱动电路43切换驱动状态使绕组产生的磁场转动以驱动转子转动，进而实现对无刷电机44的驱动。
为了驱动无刷电机44，驱动电路43至少具有六个驱动状态，为了方便说明，以下以驱动状态对应接通的接线端表示驱动状态。例如，如果控制器42控制驱动电路43使第一相绕组A连接至电源模块41的第一电源端41a以及使第二相绕组B连接至电源模块41的第二电源端41b，则该驱动状态用AB表示，在该状态下，第一相绕组A和第二相绕组B导通，称为AB相导通；如果控制器42控制驱动电路43使第一相绕组A连接至电源模块41的第二电源端41b以及使第二相绕组B连接至电源模块41的第一电源端41b，则该驱动状态用BA表示，在该状态下，第一相绕组A和第二相绕组B导通，称为BA相导通，其电流方向与AB时相反，这样表示的驱动方式同样适用于绕组的三角型连接方案。另外，驱动状态的切换也可简称为无刷电机44的换向动作。显然，转子每转过60°电角度，无刷电机44换向一次，定义无刷电机44的一次换向至下一次换向的间隔为换向区间。
图6a是驱动电路43的第一种传统的控制信号波形图。电流回路上的高侧开关(Q1、Q3、Q5)采用脉宽调制PWM信号以控制电机速度。具体地，在高侧开关中的一个的PWM信号控制期间内，低侧开关中的一个保持导通状态，该高侧开关、该低侧开关与对应的绕组构成电流回路，在该电流回路上，电源模块41的供电电流经过该第一驱动端43a、该高侧开关、绕组、该低侧开管。以控制器42控制无刷电机44使电机驱动状态处于AB状态为例，高侧开关Q1采 用PWM信号控制，在高侧开关Q1的PWM控制期间，控制器42输出低电平信号给低侧开关Q4以使其保持导通状态，该高侧开关Q1、该低侧开关Q4与对应的第一相绕组A、第二相绕组B构成电流回路，在该电流回路上，电源模块41的供电电流经过该第一驱动端43a、高侧开关Q1、第一相绕组A、第二相绕组B、低侧开管Q4、第二驱动端43b，如图7a所示。
图6b是第二种传统的控制信号波形图。电流回路上的低侧开关(Q2、Q4、Q6)采用脉宽调制PWM信号以控制电机速度。具体地，低侧开关中的一个的PWM信号控制期间内，高侧开关中的一个保持导通状态，该高侧开关、该低侧开关与对应的绕组构成电流回路，在该电流回路上，电源模块41的供电电流经过该第一驱动端43a、该高侧开关、绕组、该低侧开关、第二驱动端。以控制器42控制无刷电机44使电机驱动状态处于AB状态为例，低侧开关Q4采用PWM信号控制，在低侧开关Q4的PWM信号控制期间，控制器42输出高电平信号给高侧开关Q1以使其保持导通状态，该高侧开关Q1、该低侧开关Q4与对应的第一相绕组A、第二相绕组B构成电流回路，在该电流回路上，电源模块41的供电电流经过该第一驱动端43a、高侧开关Q1、第一相绕组A、第二相绕组B、低侧开管Q4、第二驱动端43b。
在无刷电机44运行过程中，当转子每转过60°电角度，无刷电机44换向一次，即转子每转过60°电角度，电机驱动状态从上一个状态切换到下一个状态。结合图6a、图7a和图7b，以控制器42控制无刷电机44的电机驱动状态从AB状态切换到AC状态的过程为例进行说明，其中，采用高侧开关PWM信号控制方式：控制器42输出PWM信号给高侧开关Q1的控制端AH使高侧开关Q1导通或关断，控制器42同步输出高电平信号给低侧开关Q4的控制端BL使低侧开关Q4保持导通状态，第一相绕组A和第二相绕组B通电，电机驱动状态处于AB状态(如图7a)；控制器42输出PWM信号给高侧开关Q1的控制端AH使高侧开关Q1导通或关断，控制器42同步输出低电平信号给低侧开关Q4的控制端BL使低侧开关Q4保持关断状态，控制器42同步输出高电平信号给低侧开关Q6的控制端CL使低侧开关Q6保持接通状态，电机驱动状态从AB状态切换到AC状态，第一相绕组A和第三相绕组C通电，第二相绕组B断电(如图7b)。
但由于各个开关并联有寄生二极管，在高侧开关中的一个的PWM信号控制 期间，当其从接通状态切换到断开状态时，由于回路中电感性元件的存在(例如，电机的绕组)，电流不能瞬变，电机电流会通过与该高侧开关的低侧端连接的低侧开关的寄生二极管中。如图7a所示，当电机驱动状态处于AB状态时，高侧开关Q1导通和低侧开关Q4导通，当电机驱动状态从图7a的AB状态切换到图7b的AC状态时，如图8所示，由于电感性元件的存在，电流不能瞬变，以高侧开关采用PWM信号控制方式为例，不能瞬变的电流会通过高侧开关Q3的并联寄生二极管，高侧开关Q3的寄生二极管因内部电阻而发热，使得与寄生二极管并联的高侧开关Q3以及驱动电路43温度上升。尤其是，在重载大电流状态下，其发热损耗更为严重。因此，这种传统的控制方法会带来较大的功率损失。
为了能够克服电流通过寄生二极管导致发热问题，上述技术问题，参照图9，本公开的电动工具10的控制器42被配置为：输出第一控制信号至所述高侧开关(Q1、Q3、Q5)中的一个以使该高侧开关(Q1、Q3、Q5)中的一个处于导通状态或关断状态；输出第二控制信号至低侧开关(Q2、Q4、Q6)中的一个以使该低侧开关(Q2、Q4、Q6)中的一个处于导通和关断状态中的另一个；其中，该高侧开关(Q1、Q3、Q5)中的一个的低侧端连接至该低侧开关(Q2、Q4、Q6)中的一个的高侧端，以减少发热和损耗。也即是说，在本实施方式中，第一控制信号使高侧开关中的一个处于关断状态期间，第二控制信号使与该高侧开关的低侧端直接连接的低侧开关处于导通状态，和/或第二控制信号使低侧开关中的一个处于关断状态期间，第一控制信号使与该低侧开关的高侧端直接连接的高侧开关处于导通状态。也即是说，本实施方式中，高侧开关的低侧端和低侧开关的高侧端直接连接的高侧开关和低侧开关具有相反的通断状态。这样做的好处在于，能够使不能瞬变的电流经过与该低侧开关的高侧端直接连接的高侧开关，或能够使不能瞬变的电流经过与该高侧开关的低侧端直接连接的低侧开关，而不会经过寄生二极管，以减少发热和功率损耗。
进一步地，所述控制器42输出的第一控制信号为第一PWM信号；所述控制器输42出的第二控制信号为第二PWM信号。
作为可选地，所述控制器同步输出所述第一控制信号和所述第二控制信号。
作为一种具体地实施方式，高侧开关采用PWM控制方式，控制器42被配 置为：输出第一控制信号使高侧开关中的一个处于导通状态或关断状态，第一控制信号为第一PWM信号；输出高电平信号以使低侧开关中的一个在该高侧开关的PWM信号控制期间内保持导通状态以构成电流回路；同步输出第二控制信号使与该高侧开关的低侧端连接的低侧开关处于导通和断开状态中的另一个，第二控制信号为第二PWM信号。以电机驱动状态处于AB状态为例，控制器42输出第一控制信号使高侧开关Q1处于导通状态或关断状态，第一控制信号为第一PWM信号，控制器42输出高电平信号以使低侧开关Q4在高侧开关Q1的PWM信号控制期间内保持导通状态以构成电流回路，控制器42同步输出第二控制信号使与该高侧开关Q1的低侧端连接的低侧开关Q2处于导通和断开状态中的另一个，第二控制信号为PWM信号。
作为另一种具体实施方式，低侧开关采用PWM信号控制方式，控制器42被配置为：输出第二控制信号使低侧开关中的一个处于导通状态或关断状态，第二控制信号为第二PWM信号；输出高电平信号以使高侧开关中的一个在低侧开关的PWM信号控制期间保持导通状态以构成电流回路；同步输出第一控制信号使与该低侧开关的高侧端连接的高侧开关处于导通和断开状态中的另一个，第一控制信号为第一PWM信号。以电机驱动状态处于AB状态为例，控制器42输出第二控制信号使低侧开关Q4处于导通状态或关断状态，第二控制信号为第二PWM信号；控制器42输出高电平信号使高侧开关中Q1在低侧开关Q4的PWM信号控制期间保持导通状态以构成电流回路；控制器同步输出第一控制信号使与该低侧开关Q4的高侧端连接的高侧开关Q3处于导通和断开状态中的另一个，第一控制信号为第一PWM信号。
上述仅是示例性说明，并不现实本公开的内容，必须理解的是，其他相与上述实施方类似，此处不再赘述。
参照图10，作为可选地，仅在第一PWM信号的占空比满足预设条件时，控制器42才同步输出第二PWM信号。具体地，当第一PWM信号的占空比在预设范围内时，控制器42才输出第二PWM信号。
作为可选地，至少第一PWM信号的占空比在20％～90％范围(含20％和90％)时，控制器42才输出第二PWM信号。
作为可选地，至少第一PWM信号的占空比在10％～95％范围(含10％和95％) 时，控制器42才输出第二PWM信号控制该相桥电路的低侧开关。
作为可选地，至少第一PWM信号的占空比在30％～95％范围(含30％和95％)时，控制器42才输出第二PWM信号控制该相桥电路的低侧开关。
通过这样的方式，仅在第一PWM信号满足预设条件时，控制器42才输出第二PWM信号。这样做的好处在于：一方面，当控制器42输出的第一PWM信号使其中一个高侧开关处于断开状态时，控制器42输出的第二PWM信号使与该高侧开关的低侧端连接的低侧开关处于接通状态，若第一PWM信号的占空较小，则对应绕组的电流下降较快，容易出现电流小于零情况，该小于零的电流会产生负扭矩导致制动效果而使电机转速下降，这是不利的，而若在高侧开关关断时，导通与该高侧开关的低侧端连接的低侧开关，会加剧这种不利情况，并且当第一PWM信号的占空较小时，流过该高侧开关的电流较小，产生的发热量很小，此时，控制器42也没有必要输出第二PWM信号控制与高侧开关的低侧端连接的低侧开关来减小发热和功率损耗；另一发方面，当控制器42输出的第一PWM信号使其中一个高侧开关处于断开状态时，控制器42输出的第二PWM信号使与该高侧开关的低侧端连接的低侧开关处于接通状态，若该第一PWM信号的占空比较大，则采用上述方案会使得第二PWM信号可以插入的占空比很小，其产生的作用不大，反而会由于开关的频繁开关引起开关损耗。
参照图11，作为可选地，第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长T1，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长T2。也即是说，第一预设时长T1为第一控制信号的下降沿与第二控制信号的上升沿之间的时间间隔，第二预设时长T2为第一控制信号的上升沿与第二控制信号的下降沿之间的时间间隔。
这样做的好处在于：一方面，可以避免在第一控制信号处于下降沿时，立刻开始第二控制信号的上升沿，出现高侧开关还未完全断开时，低侧开关已经接通而引起短路现象，从而烧坏电路以及电子元器件的情况发生。具体地，参照图12a，实际的方波信号由于受上升/下降时间的影响，不是严格意义上的方波信号，其上升沿和下降沿不能瞬变，而是会有小段迟滞时间T的缓慢变化。参照图12b，以A相为例，当控制器42输出的第一控制信号使高侧开关Q1关断时，控制器42输出的第二控制信号使与该高侧开关Q1的低侧端连接的低侧 开关Q2导通，若在第一控制信号处于下降沿时，立刻开始第二控制信号的上升沿，则会出现高侧开关Q1和低侧开关Q2同时导通的情况，此时会发生短路现象，容易引起电子元器件损坏甚至烧毁。采用第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长T1，可以有效避免上述短路现象发生。
另一方面，可以避免负扭矩产生而导致制动效果。具体地，参照图13a和图13b，以A相为例，在采用PWM控制期间，若负载较大，第一相绕组A的电流I1较大，则电机持续输出正向扭矩；而在轻载状态下，第一相绕组A的电流I2较小，控制器42输出的第一控制信号使高侧开关Q1处于断开状态，控制器42输出的第二控制信号使与该高侧高侧开关Q1连接的低侧开关Q2处于接通状态时，若低侧开关Q2保持接通状态较长时间，则电流I1下降较快，有可能降为负值，此时会产生负扭矩131，导致制动效果而使电机转速下降。
类似地，在采用低侧开关采用PWM控制方式中，作为可选地，所述第二PWM信号的占空比的取值范围为20％～90％。作为可选地，所述第二PWM信号的占空比的取值范围为10％～95％。作为可选地，所述第二PWM信号的占空比的取值范围为30％～95％。
采用在第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长T2，可以有效避免负扭矩产生而使电机转速下降。具体地，参照图13c，以A相为例，控制器42输出的第一控制信号施加于高侧开关Q1的控制端AH端，控制器42输出的第二控制信号施加于与高侧开关Q1的低侧端连接的低侧开关Q2的控制端AL端，在第一控制信号的每个下降沿开始后，等待第一预设时长T1开始第二控制信号的上升沿，并且在第二控制信号的下降沿开始后，等待第二预设时长T2开始第一控制信号的上升沿。其中，第一控制信号为第一PWM信号，第二控制信号为第二PWM信号。由于第一预设时长T1和第二预设时长T2的存在，不会发生高侧开关Q1和低侧开关Q2同时导通的现象，从而能够避免短路现象发生，并且由于第二预设时长T2的存在，在轻载情况下，能够避免负扭矩产生而带来制动效果使电机转速下降的情况发生。
作为可选地，第一预设时长T1的取值范围为0.5微妙～10微秒(包含端点0.5微秒和10微秒)。作为可选地，所述第二预设时长的取值范围为5微秒～30 微秒。
实际实验结果表明，当第一预设时长T1在0.5微秒～10微秒之间(包含端点0.5微秒和10微秒)时，既能够防止短路问题，同时抑制温升效果较好。
作为可选地，仅使所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长T1，以避免高侧开关和与该高侧开关的低侧端连接的低侧开关同时导通而导致短路现象发生。作为可选地，仅使所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长T2，以避免产生负扭矩而导致制动效果。以上两种实施方式与第一实施方式类似，在此不再赘述。
作为可选地，设置第一PWM信号的占空比与第二PWM信号的占空比之和小于100％，以避免高侧开关和与该高侧开关的低侧端连接的低侧开关同时导通而导致短路现象发生，和/或避免产生负扭矩而导致制动效果使电机转速下降。
对于驱动电路43，当高侧开关处于接通状态，且与该高侧开关的低侧端连接的低侧开关处于断开状态时，对应导通绕组的电流上升。反之，当高侧开关处于断开状态，且与该高侧开关的低侧端连接的低侧开关处于接通状态时，对应导通绕组的电流下降。
为了控制电动工具的电机输出保持正扭矩，以抑制电机驱动时产生负扭矩导致的制动效果，设置上述第一预设时长T1和第二预设时长T2的比值小于或等于1。作为具体实施方式，例如，设置第一预设时长T1为0.5微秒，设置第二预设时长T2为0.8微秒；再如，设置第一预设时长T1为1微秒，设置第二预设时长T2为2微秒；还如，设置第一预设时长T1为10微秒，设置第二预设时长为13微秒。上述仅是示例性说明，并非是对本公开的限制。
在此基础上，通过动态调整第二预设时长T2，使得电机绕组的电流大于或等于零，通过这样的方式，使电机不会输出负扭矩而在电机驱动时产生制动效果导致电机转速降低。
作为可选地，电动工具10还包括电流测算模块46(图4)，用于检测或估算相电流。
在采用高侧开关PWM信号控制方式中，所述控制器42被配置为：在所述 相电流小于等于零时，所述控制器42输出第二控制信号以关断所述低侧开关中的一个，以使得电机保持输出正向扭矩，所述低侧开关中的一个为与当前导通的高侧开关的低侧端连接的低侧开关。
在采用低侧开关PWM信号控制方式中，所述控制器42被配置为：在所述相电流小于等于零时，所述控制器42输出第一控制信号以关断所述高侧开关中的一个，以使得电机保持输出正向扭矩，所述高侧开关中的一个为与当前导通的低侧开关的高侧端连接的高侧开关。
在电机驱动过程中，为防止开关(Q1～Q6)温度过高而损坏电子元器件，需要对一个或多个开关(Q1～Q6)进行温度采样以监测温度。在传统的方法中，一般是将温度采样用的NTC温度传感器布置在电路板上靠近驱动电路的至少一个开关的位置，以有效监测桥开关的温度，防止温度过高而损坏电子元器件。但是，额外增加的温度传感器不但会增加电路板的设计和零部件成本，还会增加电路板的尺寸。
作为可选地，为了克服上述问题，本公开的控制器42采用内部集成有温度传感器的MCU，采用该温度传感器代替额外的温度采样用的NTC温度传感器，以估算驱动电路43的开关的温度，并且在驱动电路43的温度检测值超过预设阈值时，所述控制器42控制驱动电路43停止工作。利用控制器42内部集成的温度传感器来测算驱动电路43的温度，能够简化电路板设计，节约零部件成本，使电路板尺寸更加紧凑。在一些具体的实施方式中，所有电路板单面面积之和小于2500cm^2。
在一些具体的实施例中，采用单片机，其内部集成有温度传感器，可以用来测量CPU即周围温度，测得的结果可以用于估算驱动电路43的温度，当检测到的温度超过预设值时，开启温度保护功能，例如，关闭电动工具、开启散热风扇、关闭驱动电路43等。
上述实施例是以具有三相绕组的无刷电机44的电动工具10而言，本领域技术人员可理解的，上述技术方案也可以应用到其他具有无刷电机44的电动工具中，例如两相无刷电机。
本公开还公开了一种电动工具的控制方法，所述电动工具包括：驱动电路，包括：第一驱动端，与所述第一电源端电性连接；第二驱动端，与所述第二电 源端电性连接；多个高侧开关，所述高侧开关包括高侧端和低压端，所述高侧开关的高侧端分别电性连接至所述第一驱动端；多个低侧开关，所述低侧开关包括高侧端和低压端，所述低侧端分别电性连接至所述第二驱动端；所述电动工具的控制方法包括：使所述高侧开关中的一个处于导通状态或关断状态；使所述低侧开关中的一个处于导通和关断状态中的另一个；其中，所述高侧开关中的一个的低侧端连接至所述低侧开关中的一个的高侧端，以使不能瞬变的电流经过该低侧开关，而不会经过该低侧开关并联的寄生二极管，以减少发热和功率损耗。
作为可选地，所述第一控制信号为第一PWM信号；所述第二控制信号为第二PWM信号。
作为可选地，在所述第一控制信号满足预设条件时，控制器才输出第二控制信号。这样做的好处在于：一方面，能够避免第一PWM信号的占空比较小时加剧负扭矩产生的情况发生，以及不必要的对控制与高侧开关低侧端连接的低侧开关的通断；另一发方面，能够避免在第一PWM信号的占空比较大时，控制与高侧开关低侧端连接的低侧开关的通断，反而会由于开关的频繁开关而引起的开关损耗。
作为可选地，所述第一PWM信号的占空比的取值范围为20％～90％。
作为可选地，所述第一PWM信号的占空比的取值范围为10％～95％。
作为可选地，所述第一PWM信号的占空比的取值范围为30％～95％。
作为可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长T1。这样的好处在于，能够避免高侧开关导通时，与该高侧开关的低侧端连接的低侧开关同时导通而造成短路情况的发生。
作为可选地，所述第一预设时长T1的取值范围为5微秒～10微秒，(包含端点)既能够防止短路问题，同时抑制温升效果较好。
作为可选地，所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长T2。这样的好处在于，能够避免产生负扭矩而导致制动效果使电机转速下降。
作为可选地，所述第一控制信号的下降沿与所述第二控制信号的上升沿之 间间隔第一预设时长T1，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长T2。这样的好处在于，能够防止短路问题，同时抑制温升效果较好，并且能够避免产生负扭矩而导致制动效果使电机转速下降。
作为可选地，所述第一预设时长T1与所述第二预设时长T2的比值小于等于1。这样的好处在于，能够进一步避免产生负扭矩而导致制动效果使电机转速下降。
作为可选地，所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。这样的好处在于，能够防止短路问题的同时抑制温升和/或能够避免产生负扭矩而导致制动效果使电机转速下降。
作为可选地，电动工具的控制方法还包括：在所述相电流小于等于零时，输出第二控制信号以关断所述低侧开关中的一个，以使得电机保持输出正向扭矩。所述低侧开关中的一个为与当前导通的高侧开关的低侧端连接的低侧开关。
上述实施方式是以高侧开关采用PWM控制方式为例。对于低侧开关采用PWM控制方式而言，其控制方法与上述实施方式类似，此处不再赘述。
需要说明的是，采用低侧开关采用PWM控制方式中，作为可选地，所述第二PWM信号的占空比的取值范围为20％～90％。作为可选地，所述第二PWM信号的占空比的取值范围为10％～95％。作为可选地，所述第二PWM信号的占空比的取值范围为30％～95％。
以上显示和描述了本公开的基本原理、主要特征和优点。本行业的技术人员应该了解，上述实施例不以任何形式限制本公开，凡采用等同替换或等效变换的方式所获得的技术方案，均落在本公开的保护范围内。
工业实用性
本公开提供了一种电动工具以及控制方法，该电动工具能够有效抑制驱动电路温升，降低功率损耗。

Claims (50)

  1. 一种电动工具，包括：
    功能件，用于实现所述电动工具的功能；
    电机，用于驱动所述功能件，所述电机包括多个绕组；
    电源模块，用于提供供电电流，包括第一电源端和第二电源端；
    驱动电路，电连接至所述电机，所述驱动电路包括：
    第一驱动端，与所述第一电源端电性连接；
    第二驱动端，与所述第二电源端电性连接；
    多个高侧开关，所述高侧开关的高侧端分别电性连接至所述第一驱动端；
    多个低侧开关，所述低侧开关的低侧端分别电性连接至所述第二驱动端；
    控制器，被配置为：
    输出第一控制信号至所述高侧开关中的一个以使所述高侧开关中的一个处于导通状态或关断状态；
    输出第二控制信号至所述低侧开关中的一个以使所述低侧开关中的一个处于导通和关断状态中的另一个；
    其中，所述高侧开关中的一个的低侧端连接至所述低侧开关中的一个的高侧端。
  2. 根据权利要求1所述的电动工具，其特征在于，
    所述控制器输出的第一控制信号为第一PWM信号；所述控制器输出的第二控制信号为第二PWM信号。
  3. 根据权利要求2所述的电动工具，其特征在于，
    所述第一PWM信号的占空比的取值范围为20％～90％。
  4. 根据权利要求2所述的电动工具，其特征在于，
    所述第一PWM信号的占空比的取值范围为10％～95％。
  5. 根据权利要求2所述的电动工具，其特征在于，
    所述第一PWM信号的占空比的取值范围为30％～95％。
  6. 根据权利要求1所述的电动工具，其特征在于，
    所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长。
  7. 根据权利要求6所述的电动工具，其特征在于，
    所述第一预设时长的取值范围为5微秒～10微秒。
  8. 根据权利要求1所述的电动工具，其特征在于，
    所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
  9. 根据权利要求8所述的电动工具，其特征在于，
    所述第二预设时长的取值范围为5微秒～30微秒。
  10. 根据权利要求1所述的电动工具，其特征在于，
    所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
  11. 根据权利要求10所述的电动工具，其特征在于，
    所述第一预设时长与所述第二预设时长的比值小于等于1。
  12. 根据权利要求1所述的电动工具，其特征在于，
    所述控制器同步输出所述第一控制信号和所述第二控制信号。
  13. 根据权利要求2所述的电动工具，其特征在于，
    所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。
  14. 根据权利要求2所述的电动工具，其特征在于，
    所述第二PWM信号的占空比的取值范围为20％～90％。
  15. 根据权利要求2所述的电动工具，其特征在于，
    所述第二PWM信号的占空比的取值范围为10％～95％。
  16. 根据权利要求2所述的电动工具，其特征在于，
    所述第二PWM信号的占空比的取值范围为30％～95％。
  17. 根据权利要求1所述的电动工具，其特征在于，
    所述电动工具还包括：
    电流测算模块，用于检测或估算相电流；
    所述控制器被配置为：
    在所述相电流小于等于零时，所述控制器被配置为：输出第二控制信号以关断所述低侧开关中的一个，或输出第一控制信号控制以关断所述高侧开关中的一个。
  18. 根据权利要求1所述的电动工具，其特征在于：所述控制器包括设置于所述控制器内部的温度传感器，所述控制器根据所述温度传感器的检测值估算所述驱动电路的温度，并且在所述驱动电路的温度检测值超过预设阈值时，所述控制器控制驱动电路停止工作。
  19. 一种电动工具，包括：
    功能件，用于实现所述电动工具的功能；
    电机，用于驱动所述功能件，所述电机包括多个绕组；
    电源模块，用于提供供电电流，包括第一电源端和第二电源端；
    驱动电路，电连接至所述电机，包括：
    第一驱动端，与所述第一电源端电性连接；
    第二驱动端，与所述第二电源端电性连接；
    第一高侧开关，，所述第一高侧开关的高侧端电性连接至所述第一驱动端；
    第一低侧开关，所述第一低侧开关的低侧端电性连接至所述第二驱动端；
    控制器，被配置为：
    输出第一控制信号至所述第一高侧开关以使所述第一高侧开关处于导通状态或关断状态；
    输出第二控制信号至所述第一低侧开关以使所述第一低侧开关处于导通或关断状态中的另一个；
    其中，所述第一高侧开关的低侧端连接至所述第一低侧开关的高侧端。
  20. 根据权利要求19所述的电动工具，其特征在于，
    所述驱动电路还包括第二低侧开关，所述第二低侧开关的低侧端电性连接至所述第二驱动端；
    所述控制器被配置为：
    输出所述第一控制信号至所述第一高侧开关和所述第二低侧开关以构成第一电流回路；在所述第一电流回路中，所述电源模块提供的供电电流依次经所述第一驱动端、第一高侧开关、绕组、第二低侧开关和第二驱动端。
  21. 根据权利要求19所述的电动工具，其特征在于，
    所述控制器输出的第一控制信号为第一PWM信号；所述控制器输出的第二控制信号为第二PWM信号。
  22. 根据权利要求21所述的电动工具，其特征在于，
    所述第一PWM信号的占空比的取值范围为20％～90％。
  23. 根据权利要求21所述的电动工具，其特征在于，
    所述第一PWM信号的占空比的取值范围为10％～95％。
  24. 根据权利要求21所述的电动工具，其特征在于，
    所述第一PWM信号的占空比的取值范围为30％～95％。
  25. 根据权利要求19所述的电动工具，其特征在于，
    所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长。
  26. 根据权利要求25所述的电动工具，其特征在于，
    所述第一预设时长的取值范围为5微秒～10微秒。
  27. 根据权利要求19所述的电动工具，其特征在于，
    所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
  28. 根据权利要求19所述的电动工具，其特征在于，
    所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
  29. 根据权利要求28所述的电动工具，其特征在于，
    所述第一预设时长与所述第二预设时长的比值小于等于1。
  30. 根据权利要求19所述的电动工具，其特征在于，
    所述控制器同步输出所述第一控制信号和所述第二控制信号。
  31. 根据权利要求21所述的电动工具，其特征在于，
    所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。
  32. 根据权利要求21所述的电动工具，其特征在于，
    所述第二PWM信号的占空比的取值范围为20％～90％。
  33. 根据权利要求21所述的电动工具，其特征在于，
    所述第二PWM信号的占空比的取值范围为10％～95％。
  34. 根据权利要求21所述的电动工具，其特征在于，
    所述第二PWM信号的占空比的取值范围为30％～95％。
  35. 根据权利要求19所述的电动工具，其特征在于，
    所述电动工具还包括：
    电流测算模块，用于检测或估算相电流；
    所述控制器被配置为：
    在所述相电流小于等于零时，所述控制器被配置为输出第二控制信号以关断所述低侧开关中的一个，或输出第一控制信号控制以关断所述高侧开关中的一个。
  36. 一种电动工具的控制方法，所述电动工具包括：
    驱动电路，包括：
    第一驱动端，与所述第一电源端电性连接；
    第二驱动端，与所述第二电源端电性连接；
    多个高侧开关，所述高侧开关包括高侧端和低压端，所述高侧开关的高侧端分别电性连接至所述第一驱动端；
    多个低侧开关，所述低侧开关包括高侧端和低压端，所述低侧端分别电性连接至所述第二驱动端；
    所述电动工具的控制方法包括：
    使所述高侧开关中的一个处于导通状态或关断状态；
    使所述低侧开关中的一个处于导通和关断状态中的另一个；
    其中，所述高侧开关中的一个的低侧端连接至所述低侧开关中的一个的高侧端。
  37. 根据权利要30所述的电动工具的控制方法，其特征在于，
    所述第一控制信号为第一PWM信号；所述第二控制信号为第二PWM信号。
  38. 根据权利要求37所述的电动工具的控制方法，其特征在于，
    所述第一PWM信号的占空比的取值范围为20％～90％。
  39. 根据权利要求37所述的电动工具的控制方法，其特征在于，
    所述第一PWM信号的占空比的取值范围为10％～95％。
  40. 根据权利要求37所述的电动工具的控制方法，其特征在于，
    所述第一PWM信号的占空比的取值范围为30％～95％。
  41. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长。
  42. 根据权利要求41所述的电动工具的控制方法，其特征在于，
    所述第一预设时长的取值范围为5微秒～10微秒。
  43. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预 设时长。
  44. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第一控制信号的下降沿与所述第二控制信号的上升沿之间间隔第一预设时长，且所述第一控制信号的上升沿与所述第二控制信号的下降沿之间间隔第二预设时长。
  45. 根据权利要求44所述的电动工具的控制方法，其特征在于，
    所述第一预设时长与所述第二预设时长的比值小于等于1。
  46. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第一PWM信号的占空比和所述第二PWM信号的占空比之和小于100％。
  47. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第二PWM信号的占空比的取值范围为20％～90％。
  48. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第二PWM信号的占空比的取值范围为10％～95％。
  49. 根据权利要求36所述的电动工具的控制方法，其特征在于，
    所述第二PWM信号的占空比的取值范围为30％～95％。
  50. 根据权利要求36所述的电动工具的控制方法，其特征在于，还包括：在所述相电流小于等于零时，第二控制信号使所述低侧开关中的一个关断，或所述第一控制信号使所述高侧开关中的一个关断。
PCT/CN2019/083863 2018-05-03 2019-04-23 电动工具及其控制方法 WO2019210790A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP19796882.9A EP3780379B1 (en) 2018-05-03 2019-04-23 Electric tool
CN201980007469.9A CN111630770B (zh) 2018-05-03 2019-04-23 电动工具及其控制方法
US17/080,978 US11070164B2 (en) 2018-05-03 2020-10-27 Power tool and control method of the same
US17/354,784 US11637523B2 (en) 2018-05-03 2021-06-22 Power tool and control method of the same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201810413922.3 2018-05-03
CN201810413922 2018-05-03

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/080,978 Continuation US11070164B2 (en) 2018-05-03 2020-10-27 Power tool and control method of the same

Publications (1)

Publication Number Publication Date
WO2019210790A1 true WO2019210790A1 (zh) 2019-11-07

Family

ID=68386268

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/083863 WO2019210790A1 (zh) 2018-05-03 2019-04-23 电动工具及其控制方法

Country Status (4)

Country Link
US (2) US11070164B2 (zh)
EP (1) EP3780379B1 (zh)
CN (5) CN110434397B (zh)
WO (1) WO2019210790A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114453620A (zh) * 2020-11-09 2022-05-10 南京泉峰科技有限公司 智能电动工具及其控制方法
EP4040666A1 (de) * 2021-02-08 2022-08-10 Hilti Aktiengesellschaft Verfahren zum abbremsen eines rotierenden werkzeugs einer elektro-werkzeugmaschine und elektro-werkzeugmaschine

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113131831A (zh) * 2019-12-31 2021-07-16 南京德朔实业有限公司 电动工具与电动工具控制方式的切换方法
CN113824354A (zh) * 2020-06-18 2021-12-21 南京德朔实业有限公司 电动工具及其启动控制方法
CN113193795B (zh) * 2021-05-26 2022-12-16 深圳市好盈科技股份有限公司 一种电子调速器智能同步整流系统及其控制方法
WO2023160139A1 (zh) * 2022-02-22 2023-08-31 南京泉峰科技有限公司 电动工具及其控制方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1449082A (zh) * 2002-03-30 2003-10-15 罗伯特·博施有限公司 监控装置、电动工具机、电源装置及所属运行方法
CN101689829A (zh) * 2007-04-24 2010-03-31 罗伯特.博世有限公司 电动工具以及用于电动工具的电器开关
CN101758488A (zh) * 2008-10-30 2010-06-30 苏州宝时得电动工具有限公司 电动工具以及电动工具和电池包的组合
CN104467546A (zh) * 2013-09-25 2015-03-25 松下电器产业株式会社 电动工具
CN105291060A (zh) * 2015-12-01 2016-02-03 浙江格致工具有限公司 一种电动工具及其控制方法
CN205646881U (zh) * 2016-04-16 2016-10-12 於锋 电动工具的电子开关控制电路
US20160322834A1 (en) * 2015-04-30 2016-11-03 Active-Semi, Inc. Single-Stage AC-To-DC Switching Converter That Directly Charges A Battery Requiring A Multi-State Charging Profile
US20170373614A1 (en) * 2016-06-24 2017-12-28 Black & Decker Inc. Control scheme for power tool having a brushless motor

Family Cites Families (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2700080B1 (fr) * 1992-12-30 1995-01-27 Unite Hermetique Sa Alimentation optimale d'un moteur électrique.
US6144190A (en) * 1999-03-25 2000-11-07 Coleman Powermate, Inc. Energy conversion system employing stabilized half-bridge inverter
US6535402B1 (en) * 2002-07-12 2003-03-18 Delta Electronics Inc. Adaptive compensation of dead time for inverter and converter
JP4103906B2 (ja) * 2005-08-23 2008-06-18 オムロン株式会社 モータ制御装置
JP2008141828A (ja) * 2006-11-30 2008-06-19 Denso Corp モータ駆動装置及びモータ駆動方法
US7535684B2 (en) * 2007-01-09 2009-05-19 Honeywell International Inc. Overspeed protection for sensorless electric drives
JP5242974B2 (ja) * 2007-08-24 2013-07-24 株式会社マキタ 電動工具
JP5376392B2 (ja) * 2008-02-14 2013-12-25 日立工機株式会社 電動工具
EP2467239B1 (en) * 2010-03-31 2014-03-19 Hitachi Koki Co., Ltd. Power tool
WO2012056700A2 (en) * 2010-10-27 2012-05-03 Hitachi Koki Co., Ltd. Power tool system and power supply device
EP2675041B1 (en) * 2012-06-15 2020-05-13 Black & Decker Inc. Stator assembly for a brushless motor in a power tool
US9000497B2 (en) * 2012-09-14 2015-04-07 Renesas Electronics Corporation Trench MOSFET having an independent coupled element in a trench
JP6022319B2 (ja) * 2012-11-19 2016-11-09 ミネベア株式会社 モータの駆動制御装置
GB2515080B (en) * 2013-06-13 2016-02-24 Dyson Technology Ltd Controller for a brushless motor
US20170012572A1 (en) * 2014-02-28 2017-01-12 Hitachi Koki Co., Ltd. Work tool
JP6170455B2 (ja) * 2014-03-20 2017-07-26 日立オートモティブシステムズ株式会社 ブラシレスモータの制御装置及び制御方法
EP3427901B1 (en) * 2014-05-18 2020-03-11 Black & Decker, Inc. Convertible battery pack for power tool
US10322498B2 (en) * 2014-10-20 2019-06-18 Makita Corporation Electric power tool
JP6545064B2 (ja) * 2015-09-30 2019-07-17 株式会社マキタ モータの制御装置
JP6953113B2 (ja) * 2016-05-30 2021-10-27 マックス株式会社 工具
JP6845655B2 (ja) * 2016-10-04 2021-03-24 株式会社マキタ 電動作業機

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1449082A (zh) * 2002-03-30 2003-10-15 罗伯特·博施有限公司 监控装置、电动工具机、电源装置及所属运行方法
CN101689829A (zh) * 2007-04-24 2010-03-31 罗伯特.博世有限公司 电动工具以及用于电动工具的电器开关
CN101758488A (zh) * 2008-10-30 2010-06-30 苏州宝时得电动工具有限公司 电动工具以及电动工具和电池包的组合
CN104467546A (zh) * 2013-09-25 2015-03-25 松下电器产业株式会社 电动工具
US20160322834A1 (en) * 2015-04-30 2016-11-03 Active-Semi, Inc. Single-Stage AC-To-DC Switching Converter That Directly Charges A Battery Requiring A Multi-State Charging Profile
CN105291060A (zh) * 2015-12-01 2016-02-03 浙江格致工具有限公司 一种电动工具及其控制方法
CN205646881U (zh) * 2016-04-16 2016-10-12 於锋 电动工具的电子开关控制电路
US20170373614A1 (en) * 2016-06-24 2017-12-28 Black & Decker Inc. Control scheme for power tool having a brushless motor
EP3296063A1 (en) * 2016-06-24 2018-03-21 Black & Decker Inc. Control scheme for power tool having a brushless motor

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114453620A (zh) * 2020-11-09 2022-05-10 南京泉峰科技有限公司 智能电动工具及其控制方法
CN114453620B (zh) * 2020-11-09 2024-01-05 南京泉峰科技有限公司 智能电动工具及其控制方法
EP4040666A1 (de) * 2021-02-08 2022-08-10 Hilti Aktiengesellschaft Verfahren zum abbremsen eines rotierenden werkzeugs einer elektro-werkzeugmaschine und elektro-werkzeugmaschine
WO2022167114A1 (de) * 2021-02-08 2022-08-11 Hilti Aktiengesellschaft Verfahren zum abbremsen eines rotierenden werkzeugs einer elektro-werkzeugmaschine und elektro-werkzeugmaschine
WO2022167113A1 (de) * 2021-02-08 2022-08-11 Hilti Aktiengesellschaft Verfahren zum abbremsen eines rotierenden werkzeugs einer elektro-werkzeugmaschine und elektro-werkzeugmaschine

Also Published As

Publication number Publication date
EP3780379A1 (en) 2021-02-17
CN110445427B (zh) 2021-11-19
US20210320613A1 (en) 2021-10-14
CN110460269B (zh) 2021-08-27
CN110460269A (zh) 2019-11-15
CN111630770B (zh) 2023-11-03
CN110434791B (zh) 2021-08-27
CN110434397B (zh) 2021-08-27
CN111630770A (zh) 2020-09-04
US20210044248A1 (en) 2021-02-11
CN110445427A (zh) 2019-11-12
US11637523B2 (en) 2023-04-25
US11070164B2 (en) 2021-07-20
EP3780379A4 (en) 2021-04-21
CN110434791A (zh) 2019-11-12
CN110434397A (zh) 2019-11-12
EP3780379B1 (en) 2022-01-19

Similar Documents

Publication Publication Date Title
WO2019210790A1 (zh) 电动工具及其控制方法
US9154009B2 (en) Brushless motor continuation control in a power tool
US11095238B2 (en) Electric tool and control method of electric tool
JP2013243824A (ja) ３相ブラシレスモータの制動装置
US20170099025A1 (en) Power Tool
US10898985B2 (en) Power tool
US10972023B2 (en) Power tool and control method thereof
JP6953113B2 (ja) 工具
JP2004015986A (ja) モータの制御装置
CN115383664A (zh) 电动工具及其控制方法
EP3852267A1 (en) Power-on self-test method for an electric power tool and electric power tool
EP4307555A1 (en) Power tool
EP4207583A1 (en) Electric tool
US20230125520A1 (en) Power tool and control method thereof
EP4231519A1 (en) Power tool and control method therefor
CN116683404A (zh) 电动工具及其控制方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19796882

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 19 796 882.9

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2019796882

Country of ref document: EP

Effective date: 20201030