WO2018153327A1 - 适用于电机的控制电路和电动工具 - Google Patents

适用于电机的控制电路和电动工具 Download PDF

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Publication number
WO2018153327A1
WO2018153327A1 PCT/CN2018/076730 CN2018076730W WO2018153327A1 WO 2018153327 A1 WO2018153327 A1 WO 2018153327A1 CN 2018076730 W CN2018076730 W CN 2018076730W WO 2018153327 A1 WO2018153327 A1 WO 2018153327A1
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WO
WIPO (PCT)
Prior art keywords
brake
branch
switch
braking
control circuit
Prior art date
Application number
PCT/CN2018/076730
Other languages
English (en)
French (fr)
Inventor
段俊雅
孙石磊
谢志斌
杨洋
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
Priority claimed from CN201711391174.5A external-priority patent/CN108512463B/zh
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 EP18756583.3A priority Critical patent/EP3567716B1/en
Publication of WO2018153327A1 publication Critical patent/WO2018153327A1/zh
Priority to US16/533,079 priority patent/US10892691B2/en

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    • 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
    • H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
    • H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
    • H02P3/08—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing a dc motor
    • 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
    • H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
    • H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
    • H02P3/08—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing a dc motor
    • H02P3/12—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing a dc motor by short-circuit or resistive braking

Definitions

  • the present invention relates to the field of motor control, and more particularly to a control circuit suitable for a motor and a power tool including the same.
  • the main function of the motor is to generate drive torque, which is a power source for electrical appliances or various machines to convert electrical energy into mechanical energy.
  • motors are used to connect work components to drive the work components to perform the functions.
  • the operation switch of the power tool When the operation switch of the power tool is closed, the power supply of the power tool and the motor form a closed power supply circuit to drive the motor to work.
  • the operation switch When the operation switch is opened, although the power supply circuit is disconnected, the motor and the working components it drives are inertia. It is not possible to end the action immediately, and it is easy to cause damage to the operator.
  • the tool In the case of angular grinding, the tool is often used for cutting and grinding.
  • the grinding disc is a working part of the angle grinder. When the operator releases the operating switch, he hopes to stop the rotation of the motor as soon as possible to avoid high-speed rotating grinding. The disc is damaged by human touch or other reasons.
  • a control circuit suitable for a motor includes a driving state and a braking state
  • the motor includes a stator winding and a rotor
  • the control circuit includes:
  • a drive branch comprising a branch formed by the stator winding, a drive switch and a rotor, the drive switch for controlling conduction or disconnection of a connection between the stator winding and the rotor;
  • a brake branch comprising a stator winding, a brake switch and a branch formed by an electrical energy storage element, the electrical energy storage element for providing electrical energy to the brake branch, the electrical energy storage element being disposed on two of the rotor Between the ends;
  • control unit electrically connecting the main control switch, the drive switch and the brake switch, respectively, to control closing or opening of the main control switch, the drive switch and the brake switch;
  • the driving branch stator winding and the rotor are electrically connected.
  • a diode is connected in series between the electrical energy storage element and the rotor to charge and discharge the electrical energy storage element.
  • the drive switch is connected in series between the stator winding and the rotor for controlling conduction or disconnection of a connection between the stator winding and the rotor.
  • control unit includes a brake drive circuit that transmits a pulse signal to the brake switch in a driving state to control the closing or opening of the brake switch.
  • the brake branch is further provided with a current detecting unit, wherein the current detecting unit is configured to detect whether the braking current on the brake branch exceeds a preset threshold in a braking state, and if so, the controlling The circuit controls the brake switch to be in an open state for shutting off conduction between the electrical energy storage element and the stator winding.
  • the control circuit controls the drive switch to close, so that the current between the stator winding and the rotor is turned on.
  • the brake branch further includes a first brake control switch and a second brake control switch; from one end of the stator winding to the other end thereof, the brake branch includes the first one in series A brake control switch, the electrical energy storage element, the brake switch, and the second brake control switch.
  • control circuit includes a voltage detecting unit configured to detect whether the brake switch is short-circuited in a driving state, and if so, the control circuit controls the first brake control switch and The second brake control switch causes the brake branch to be non-conducting in the braking state.
  • the control circuit controls the first brake control switch and/or the second brake control switch to open to cut off the The conduction of the brake branch.
  • control unit includes: a first voltage detecting unit, a brake driving circuit, a first brake protection circuit, a second brake protection circuit, and a central processor, wherein the brake branch is further provided with a second voltage detection unit;
  • the first voltage detecting unit is configured to detect a first voltage at a connection point of the brake switch and the second brake control switch in a driving state, and send the first voltage to the central processor ;
  • the second voltage detecting unit is disposed between the brake switch and the electric energy storage element for outputting a second voltage to the first brake protection circuit
  • the central processor Determining, by the central processor, whether the brake switch is short-circuited according to the first voltage, thereby controlling whether the brake branch is turned on in a braking state; the central processor is in the braking state to the The brake drive circuit sends a pulse signal;
  • the first brake protection circuit outputs a first protection signal or a second protection signal to the brake drive circuit according to the second voltage; when the first brake protection circuit outputs a first to the brake drive circuit a first protection signal is output to the second brake protection circuit when the signal is protected;
  • the brake driving circuit generates a first driving signal according to the pulse signal and the first protection signal, the first driving signal is a signal for controlling the braking switch to be periodically closed; the braking driving circuit is according to the The pulse signal and the second protection signal generate a second driving signal, and the second driving signal is a signal for controlling the opening of the brake switch;
  • the second brake protection circuit generates a fourth protection signal according to the third protection signal, and the fourth protection signal is a signal for controlling the driving switch to be turned off.
  • the first brake protection circuit employs a self-locking circuit.
  • the driving branch stator winding and the rotor are electrically connected.
  • the present invention also provides a power tool including a housing on which an operation switch and a working member are disposed, a motor for driving the working member is disposed in the housing, and the power tool further includes the above Any of the above applies to the control circuit of the motor.
  • the power tool is an angle grinder
  • the working component is a sanding disc.
  • a control circuit suitable for a motor including a stator winding and a rotor, the control circuit including a driving branch and a braking branch, the control circuit including a driving state and a braking state ,
  • the drive branch includes a branch formed by a stator winding and a rotor;
  • the brake branch includes a stator winding, a brake switch, and a branch formed by an electrical energy storage element, the electrical energy storage element for providing electrical energy to the brake branch;
  • the driving branch stator winding and the rotor are electrically connected.
  • the driving branch stator winding and the rotor are disconnected, the braking branch short circuit is detected, and the braking branch is cut off, so that the driving branch stator winding and the rotor are electrically connected.
  • a drive switch is disposed between the stator winding and the rotor. In the braking state, if the brake switch has a short circuit fault, the drive switch is closed to conduct the stator winding and the rotor connection.
  • the stator winding of the motor and the rotor are electrically connected.
  • At least one brake control switch is further disposed on the brake branch, and if the brake switch has a short-circuit fault, at least one of the brake control switches is opened to cut off the brake branch.
  • a diode is connected in series between the electrical energy storage element and the rotor to charge and discharge the electrical energy storage element.
  • control circuit includes a brake circuit that transmits a pulse signal to the brake switch in a braking state to control the closing or opening of the brake switch.
  • the brake branch is further provided with a current detecting unit, wherein the current detecting unit is configured to detect whether the braking current on the brake branch exceeds a preset threshold in a braking state, and if yes, open the The brake switch is used to cut off conduction between the electrical energy storage element and the stator winding.
  • the driving branch stator winding and the rotor are electrically connected.
  • the present invention also provides a power tool including a housing on which an operation switch and a working member are disposed, a motor for driving the working member is disposed in the housing, and the power tool further includes the above A control circuit suitable for a motor as described in any of the above.
  • the power tool is an angle grinder
  • the working component is a sanding disc.
  • a control circuit suitable for a motor including a stator winding and a rotor, the control circuit including a driving branch and a braking branch, the control circuit including a driving state and a braking state ,
  • the drive branch In the braking state, if it is detected that the braking parameter of the brake branch exceeds a predetermined value, the drive branch is turned on.
  • the driving branch includes a branch formed by the stator winding and the rotor; in the braking state, if it is detected that the braking force generated by the braking branch exceeds a predetermined value, the driving branch stator winding and the rotor are turned on connection.
  • the driving branch stator winding and the rotor are disconnected, the braking branch short circuit is detected, and the braking branch is cut off, so that the driving branch stator winding and the rotor are electrically connected.
  • a drive switch is disposed between the stator winding and the rotor. In the braking state, if the brake switch has a short circuit fault, the drive switch is closed to conduct the stator winding and the rotor connection.
  • the stator winding of the motor and the rotor are electrically connected.
  • the driving branch stator winding and the rotor are electrically connected.
  • the present invention also provides a power tool including a housing on which an operation switch and a working member are disposed, a motor for driving the working member is disposed in the housing, and the power tool further includes the above A control circuit suitable for a motor as described in any of the above.
  • the power tool is an angle grinder
  • the working component is a sanding disc.
  • control circuit suitable for the motor and the power tool including the control circuit can cause the rotor of the motor to stop rotating as soon as possible after the driving state is exited, and avoid the high-speed rotating working parts to the operator and other personnel. Brings unnecessary damage; can effectively control the braking current in the brake branch under braking state, avoiding the burnout of the stator winding due to excessive braking current and even unnecessary braking Personal injury.
  • Figure 1 is a schematic view showing the structure of an angle grinder as one of the embodiments
  • Figure 2 is a first circuit diagram of a control circuit suitable for a motor
  • FIG. 3 is a schematic diagram of a drive current path of the control circuit applicable to the motor in FIG. 2 in a driving state;
  • FIG. 4 is a schematic diagram of a charging current path of the control circuit applicable to the motor in FIG. 2 in a driving state;
  • Figure 5 is a schematic diagram of the braking current path of the control circuit of Figure 2 applied to the motor in a braking state;
  • FIG. 6 is a schematic diagram of a charging current path of the control circuit applicable to the motor in the braking state of FIG. 2;
  • Figure 7 is a second circuit diagram of a control circuit suitable for a motor
  • Figure 8 is a third circuit diagram of a control circuit suitable for a motor
  • Figure 9 is a block diagram of the control circuit of Figure 8.
  • Figure 10 is a circuit diagram of a first voltage detecting unit in the control circuit
  • Figure 11 is a circuit diagram of a first brake protection circuit in a control circuit
  • Figure 12 is a circuit diagram of a second brake protection circuit in the control circuit
  • Figure 13 is a control flow chart of the control circuit of Figure 8 applied to the motor;
  • Figure 14 is a fourth circuit diagram of a control circuit suitable for a motor
  • Figure 15 is a fifth circuit diagram of a control circuit suitable for use in a motor
  • Figure 16 is a sixth circuit diagram of a control circuit suitable for use in a motor.
  • the power tool uses an angle grinder 100 as an example.
  • the electric tool can also be other tools that can convert the output torque into other forms of motion.
  • These tools may be used to polish workpieces, such as sanders; these tools are also used. May be used to cut workpieces, such as reciprocating saws, circular saws, jigsaws; these tools may also be used for impact applications, such as electric hammers; these tools may also be garden tools such as pruners and chainsaws; It may also be used for other purposes, such as a blender.
  • these power tools include the motor 120 that drives the movement of its working components, the substance of the technical solutions disclosed below can be employed.
  • the angle grinder 100 shown in FIG. 1 includes a housing, and a sanding disc 110 and an operation switch 140 disposed on the housing.
  • the motor 120 and its control circuit are disposed in the housing, and a power source extending outward from the housing. Cable 130.
  • the sanding disc 110 is used to implement a tool function such as sanding or cutting, and the motor 120 drives the sanding disc 110 to operate with the power turned on.
  • the power cable 130 includes two connection terminals for accessing electrical energy to power the motor 120.
  • the power cable 130 can be connected to a direct current or an alternating current power source.
  • the power cable 130 is an AC plug, and the AC power is inserted to supply power to the motor 120.
  • the operation switch 140 is a push operation switch 140, a gear operation switch 140 or other switch that can be operated by a user.
  • the operation switch 140 is disposed at a position on the outer casing of the angle grinder 100 for the user to operate.
  • the control circuit of the motor turns on the power supply path between the motor 120 and the power cable 130;
  • the control circuit of the motor cuts off the power supply path between the motor 120 and the power cable 130.
  • the grinding wheel 110 is mounted or fixed on the output shaft of the motor 120, and the rotor rotates to drive the output shaft to rotate, thereby driving the sanding disc 110 to perform grinding or cutting work. It should be noted that any device that can be rotated by the rotor is considered to be the output shaft of the present invention.
  • the operation switch 140 When the operation switch 140 is released by the user, the rotor still drives the sanding disc 110 to rotate under the action of inertia. At this time, if a braking force opposite to the direction of rotation is applied to the rotor, the rotor can be stopped as soon as possible to avoid the high-speed rotating sanding disc. 110 causes unnecessary harm to the operator and other personnel.
  • the control circuit of the motor in FIG. 2 includes a main control switch 151, a driving branch, a braking branch and a control unit 180; the control circuit includes a driving state and a braking state when the main control When the switch 151 is closed, the control circuit is in a driving state, and when the main control switch 151 is off, the control circuit is in a braking state.
  • the control unit 180 detects that the operation switch 140 disposed on the tool housing is triggered, then closes the main control switch 151, the control circuit is in the driving state, and the control unit 180 detects that the operation switch 140 is released, then opens the main control switch 151, and the control circuit Is in a braking state.
  • the main control switch 151 is disposed on the power supply path between the driving branch and the external power source. When the main control switch 151 is closed, the control circuit enters a driving state, and when the main control switch 151 is turned on, the control circuit enters a braking state.
  • the first end of the main control switch 151 is electrically connected to the first power end 131 of the power cable 130, the second end is electrically connected to the first end of the driving branch, and the second end of the power cable 130 is driven and driven.
  • the second end of the branch is electrically connected, and the main control switch 151 is configured to establish and cut off an electrical connection between the driving branch and the power cable 130.
  • the above motor can be a series excitation motor, a series excitation motor, a shunt motor, a synchronous motor or an asynchronous motor.
  • a series motor or a series motor is taken as an example, including a stator winding 122 and a rotor 121, and the driving branch includes The stator winding 122, the drive switch 152 and the rotor 121 are connected in series; the brake branch includes a stator winding 122, a brake control switch group and a branch formed by the electrical energy storage element 170 in series.
  • the driving switch 152 is connected in series between the stator winding 122 and the rotor 121 to form a driving branch.
  • the first end of the stator winding 122 serves as the first end of the driving branch and the first end of the main control switch 151.
  • the second end is electrically connected, the second end of the stator winding 122 is electrically connected to the first end of the driving switch 152, the second end of the driving switch 152 is electrically connected to the first end of the rotor 121, and the second end of the rotor 121 is used as
  • the second end of the driving branch is electrically connected to the second power end 132 of the power cable 130.
  • the driving switch 152 In the driving state, the driving switch 152 is closed, the stator winding 122 and the rotor 121 are turned on, and the current flowing through the stator winding 122 causes the stator winding 122 to generate a magnetic field that drives the rotation of the rotor 121, and the rotation of the rotor 121 drives the output shaft to rotate, thereby driving
  • the sanding disc 110 connected to one end of the output shaft operates.
  • the driving switch 152 is one of power devices, such as a MOS tube, a thyristor, or the like.
  • the brake control switch group includes a first brake control switch 161 and a second brake control switch 162.
  • the first end of the first brake control switch 161 is electrically connected to the first end of the stator winding 122, and the second end is electrically connected
  • the first end of the storage element 170 is electrically connected, the second end of the electrical energy storage element 170 is grounded;
  • the first end of the second brake control switch 162 is electrically connected to the second end of the stator winding 122, and the second brake control switch
  • the second end of the 162 is electrically connected to the second end of the electrical energy storage element 170, and the brake control switch group, the electrical energy storage element 170, and the stator winding 122 form a brake branch by the above connection manner.
  • the first brake control switch 161 may be one of a relay, a field effect transistor or a thyristor
  • the second brake control switch 162 may be one of a relay, a field effect transistor or a thyristor.
  • the electrical energy storage element 170 is a source of electrical energy for the brake branch. To stabilize the direction of the braking current of the brake branch, the electrical energy storage element 170 employs a capacitance with polarity coupled in parallel across the rotor 121. Since the electric energy storage element 170 adopts a capacitor with polarity, it can only be charged and discharged in one direction. When the motor 120 is normally operated in the AC power source, an induced electromotive force that periodically changes in direction is generated, so that the first end of the rotor 121 and the electric energy are generated.
  • a diode D3 is connected in series between the first end of the storage element 170, a cathode of the diode D3 is electrically connected to the first end of the electrical energy storage element 170, and an anode of the diode D3 is electrically connected to the first end of the rotor 121 to form The charging branch; the addition of diode D3 ensures that the varying induced electromotive force can only charge the capacitor in one direction, avoiding charging in the opposite direction and damaging the capacitor.
  • a bleeder resistor R is also connected in parallel across the two ends of the electrical energy storage element 170. The electrical energy storage element 170 and the bleeder resistor R form a discharge loop to effect a slow discharge of the capacitor.
  • the control unit 180 detects that the operation switch 140 is switched from the open state to the closed state, and the control master is controlled.
  • the switch 151 and the drive switch 152 are closed, and the power cable 130 is connected to the drive branch to supply power to the motor 120.
  • a current path is formed as shown by 301 in FIG. 3, and a current flows from the power source through the first power terminal 131 through the main control switch 151 to enter the driving branch.
  • the circuit flows through the stator winding 122, the drive switch 152, and the rotor 121 in turn, and then returns to the power source by the second power terminal 132, thereby driving the motor 120 to operate.
  • a charging branch current path as shown in FIG. 401 is formed, and the current flows through the first power supply terminal 131, and sequentially passes through the main control switch 151, the stator winding 122, and the driving switch 152. After that, the electrical energy storage component 170 returns to the second power terminal 132 to form a charging branch to charge the electrical energy storage component 170.
  • the current flows through the first end of the electrical energy storage element 170 through the first brake control switch 161, the stator winding 122, the second brake control switch 162, and then back to the second end of the electrical energy storage element 170.
  • the stator winding 122 generates a magnetic field due to a braking current and acts on the rotor 121.
  • the movement of the rotor 121 in the magnetic field generated by the braking current generates an electromotive force, and when it generates an electromotive force higher than the electromotive force of the electrical energy storage element 170, it is possible to The storage element 170 is charged, and the energy of the rotor 121 is further consumed.
  • the current flows through the diode D3 and the electrical energy storage element 170 through the first end of the rotor 121, and then returns to the rotor 121, and flows through the rotor 121.
  • the current the magnetic field generated by the braking current in the stator winding 122, can apply a braking force thereto, thereby rapidly reducing the rotational speed of the rotor 121.
  • the freewheeling diodes D1 and D2 may be connected across the stator winding 122, and the anodes of the diodes D1 and D2 are both The second end of the second brake control switch 162 is electrically connected, and the cathodes of the freewheeling diodes D1 and D2 are electrically connected to the second end of the first brake control switch 161 through the freewheeling diodes D1, D2 and the stator.
  • Winding 122 forms a freewheeling circuit that causes the electrical energy of stator winding 122 to be consumed in a freewheeling manner in the circuit, providing a certain protection against stator windings 122.
  • the control circuit in this embodiment further includes a brake switch 163, that is, a brake switch 163 is added to the brake branch, and the first end of the brake switch 163 is electrically connected to the second
  • the second end of the brake control switch 162 is electrically connected to the second end of the electrical energy storage element 170; the brake switch 163 is electrically connected to the control unit 180, and the control unit 180 can control the brake according to the magnitude of the braking current.
  • the brake switch 163 it may be a short circuit fault before the control circuit enters the braking state, or a short circuit fault may occur during the braking state, and the voltage at both ends may also have different amplitudes depending on the state of the state. Or amplitude range.
  • the brake branch is not turned on. If the short circuit occurs at the brake switch 163, since the second end of the brake switch 163 is grounded, the voltage at the first end is pulled down by the ground end. It is close to 0, and under normal conditions, it may be +5V (triode collector voltage).
  • the brake switch 163 can be detected before the control circuit enters the braking state. If the brake switch 163 has been short-circuited, the control circuit no longer turns on the brake branch after the operation switch 140 is opened.
  • the control unit 180 If the brake switch 163 is short-circuited when the control circuit is in the braking state or is a pulse signal error sent by the control unit 180, for example, the control unit 180 always outputs a high level, which easily causes the braking current to become larger, with the brake The current becomes larger, and the control of the brake branch can be realized by setting the current detecting unit for detecting the current on the brake branch; when the brake current is increased, the voltage at the second end of the brake switch 163 is also Since the increase is made, the voltage threshold can be set accordingly to determine the brake current, thereby further controlling the brake branch.
  • the second voltage detecting unit 190 is further disposed on the brake branch, and the second voltage detecting unit 190 is electrically connected to the second switch 163. Between the end and the ground, the voltage at the second end of the brake switch 163 is detected in the braking state.
  • the central processing unit 181 is respectively associated with the main control switch 151 (corresponding to the a node), the drive switch 152 (corresponding to the b1 node), the first brake control switch 161 (corresponding to the f node), and the second brake control switch 162 (corresponding to the g node).
  • the first voltage detecting unit 182 is electrically connected to the first end of the brake switch 163 (corresponding to the c-node), and the brake driving circuit 183 is electrically connected to the brake switch 163 (corresponding to the e-node).
  • the first voltage detecting unit 182 is configured to detect the voltage U1 at the first end of the brake switch 163, and the central processor 181 determines whether the brake switch 163 has a short circuit fault according to the voltage value detected by the first voltage detecting unit 182, and if so, Then, the brake branch is not turned on in the braking state, otherwise, it is normally turned on; the central processor 181 sends a pulse signal to the brake driving circuit 183 in the braking state, and sends it to the brake driving circuit 183;
  • the dynamic protection circuit 185 outputs a first protection signal or a second protection signal according to the detection result of the second voltage detecting unit 190, and transmits the first protection signal or the second protection signal to the brake driving circuit 183;
  • the braking driving circuit 183 is The pulse signal and the first protection signal sent by the central processing unit 181 generate a first driving signal, the first driving signal is a signal for controlling the periodic closing of the brake switch 163; and the braking driving circuit 183 is based on the pulse transmitted by the central processing
  • control unit 180 may further include a second brake protection circuit 185, and the second brake protection circuit 185 and the first brake protection circuit 184 are electrically connected.
  • the drive switch 152 Connected to the drive switch 152 (corresponding to the b2 node); when the first brake protection circuit 184 outputs the second protection signal to the brake switch 163, the third protection signal is output to the second brake protection circuit 186, The second brake protection circuit 185 generates a fourth protection signal according to the third protection signal, and the fourth protection signal is a signal that controls the drive switch 152 to be turned off. After the drive switch 152 is turned off, a portion of the brake current in the stator winding 122 flows downward through the rotor 121, partially canceling the current that the capacitor 121 charges for the capacitor, thereby reducing the braking current.
  • the first voltage detecting unit 182 in FIG. 9 can adopt the circuit structure shown in FIG. 10.
  • the first voltage detecting unit 182 includes two diodes D11 and D12 connected in series, and the poles of the diodes D11 and D12.
  • the cathode of the diode D11 is connected to the first end of the brake switch 163 (c node)
  • the anode of the diode D11 is connected to the cathode of the D12
  • the anode of the D12 is grounded on the one hand through the series circuit of the resistor R11 and the capacitor C11, and the other
  • the aspect is connected to the +5V DC power supply through the resistor R12.
  • One end of the resistor R11 and the capacitor C11 (Braking_AD) is connected to the central processing unit 181.
  • the brake switch 163 When the circuit does not enter the braking state, the brake switch 163 is not short-circuited, and the voltage at the point c is high (switched DC The power supply is generally +5V), at this time, the diode is not turned on, and the voltage value U1 outputted by the Braking_AD terminal is a high level signal; if the brake switch 163 is short-circuited, the voltage at the point c is pulled low by the ground terminal, the diode D11, D12 is turned on, and the voltage value U1 outputted by the Braking_AD terminal is a low level signal.
  • the central processing unit 181 can know whether the brake switch 163 is short-circuited according to a preset determination threshold.
  • the second end and the second voltage detecting unit 190 (node d), the second end of the resistor R22 is connected to the first end of the resistor 23 on the one hand, and the parallel branch formed by the capacitor C21 and the capacitor C22 is grounded on the other hand;
  • the triode Q21 is an NPN type triode whose base is connected to the second end of the resistor R22 through a resistor R24, the emitter is grounded, the collector is connected to the cathode of the Schottky diode D22, and the anode (protectl end) of the Zener diode D22 is connected to the brake drive.
  • the Pro_AD node When the first brake protection circuit 184 outputs a low level signal to the second brake protection circuit 185, the Pro_AD node is a low level signal, the transistor Q31 is not turned on, and the low level signal is output at the b2 node, and the drive switch 152 is controlled.
  • the Pro_AD node When the first brake protection circuit 184 outputs a high level signal to the second brake protection circuit 185, the Pro_AD node is a low level signal, the transistor Q31 is turned on, and the high level signal is output at the b2 node, and the drive switch is controlled. 152 closed.
  • the above control process applied to the control circuit of the motor is further explained, and the first voltage threshold Vth1 and the second voltage threshold Vth2 are set.
  • the central processing unit 181 detects that the operation switch is switched from the open state to the closed state, and then opens the brake control switch 161 in the brake control switch group. , 162 and the brake switch 163, the main control switch 151 is turned off, the control circuit enters the driving state, and the driving switch 152 is turned off. At this time, the driving branch is turned on, and the braking branch is not turned on; the first voltage detecting unit 182 detects the system. The voltage U1 at the first end of the switch 163 is sent, and the detection result is sent to the central processing unit 181 for threshold determination.
  • the first brake guarantee The protection circuit 185 sends a first protection signal to the brake drive circuit 183, the first protection signal is a high level signal, and the brake drive circuit 183 generates a first drive signal in combination with the pulse signal and the first protection signal, that is, can control the brake switch 163 periodically turning off and on the pulse signal;
  • the first brake protection circuit 184 sends a second protection signal to the brake drive circuit 183, and the second protection signal is a low level signal
  • the brake drive circuit 183 in combination with the pulse signal and the second protection signal, generates a second driving signal, that is, a low level signal capable of controlling the opening of the brake switch 163; meanwhile, the first brake protection circuit 184 outputs a third protection to the second brake protection circuit 185.
  • the signal, the third protection signal is a high level signal
  • the second brake protection circuit 185 generates a fourth protection signal according to the third protection signal, that is, a signal high level signal capable of controlling the switch 152 to
  • the second brake protection circuit 186 is electrically connected to the first brake control switch 161 and/or the second brake control switch 162 in the control circuit of the motor, when the first brake protection circuit 184 outputs a third protection signal to the second brake protection circuit 185 while outputting the first protection signal to the brake switch 163, and the second protection circuit 185 generates a fifth protection signal according to the third protection signal, the fifth protection signal.
  • the signal that the second brake protection circuit 185 is open to the first brake control switch 161 and/or the second brake control switch 162. After the first brake control switch 161 and/or the second brake control switch 162 are opened, the brake branch cannot continue to be turned on, thereby reducing the braking current.
  • control of the braking current can also be realized by opening the combination of the first brake control switch 161 and/or the second brake control switch 162 and the closing of the drive switch 152.
  • the driving branch stator winding and the rotor itself are disconnected; if a braking branch short circuit is detected during a certain period of time, or when a braking state is detected
  • the braking parameter during the moving process exceeds a predetermined value, or when the braking force generated by the braking branch exceeds a predetermined value, the braking branch is cut off, the connection between the stator winding of the driving branch and the rotor is turned on, and the driving branch is generated.
  • the driving force can offset the braking force generated by the brake branch. At this time, the braking force generated by the brake branch is zero because the brake branch has been cut off.
  • the driving branch stator winding and the rotor itself are electrically connected; if a braking branch short circuit is detected during a certain period of time, or when a braking state is detected or The braking parameter during the braking process exceeds a predetermined value, or when the braking force generated by the braking branch is detected to exceed a predetermined value, the braking branch may not be cut, and the driving stator winding and the rotor itself are connected to each other.
  • the driving force can offset the braking force generated by the brake branch.
  • the present invention provides a control circuit suitable for a motor, the motor including a stator winding and a rotor, the control circuit including a drive branch and a brake branch, the control circuit including a drive state and a brake state;
  • the driving branch In the braking state, if it is detected that the braking parameter of the braking branch exceeds a predetermined value, the driving branch is turned on, and the driving force generated by the driving branch is used to resist or offset the braking branch generation system. Power or braking force.
  • the driving branch is turned on here, and the driving circuit may be continuously turned on or partially turned on. In one embodiment of the invention, partial conduction of the drive circuit can be achieved by adjusting the duty cycle.
  • the driving branch includes a branch formed by the stator winding and the rotor, and when the braking state is detected or the braking parameter of the braking process exceeds a predetermined value or the braking force generated by the braking branch exceeds a predetermined value, the driving The branch stator winding and the rotor are electrically connected, and the driving force generated by driving the branch stator winding and the rotor conduction connection is used to resist or cancel the braking force or braking force generated by the brake branch.
  • the main difference between the control circuit and FIG. 7 and FIG. 8 is that only the brake switch 163 is included in the brake branch, and the conduction of the brake switch 163 is described in the above embodiments. Both the cutting control and the short-circuit failure detecting method are applicable to the present embodiment.
  • the control circuit comprises: a driving branch and a braking branch, the driving branch comprises a stator winding 122, a driving switch 152 and a branch formed by the rotor 121 in series, and the driving branch is electrically connected to the external power source in the driving state, in the braking state
  • the brake branch includes a branch formed by the stator winding 122, the brake switch 163 and the electrical energy storage element 170 connected in series, and the electrical energy storage element 170 is used to supply electrical energy to the brake branch, and the electrical energy storage element 170 passes
  • a diode D3 is connected between both ends of the rotor 121.
  • the stator winding 122 is again caused to generate a second driving force that drives the rotation of the rotor 121 to cancel a portion of the braking force generated on the brake branch it generates.
  • the stator winding of the driving branch and the rotor itself are disconnected. If the braking branch is short-circuited within a certain period of time, the braking branch can be turned off and the stator winding and the rotor of the driving branch can be turned on.
  • the connection, the driving force generated by the driving branch can offset the braking force generated by the braking branch.
  • control circuit can also be in the braking state and the driving state, and the stator winding and the rotor are always in the on state, that is, as shown in FIG. 15, the driving switch 150 in the driving branch is removed, and similarly, in the above
  • the control for turning on or off the brake switch 163 and the short-circuit failure detecting method described in the embodiments are applicable to the present embodiment, and the functions of the remaining components in the control circuit described in each of the above embodiments are also applicable to the present embodiment. .
  • the control circuit comprises: a driving branch and a braking branch, the driving branch comprises a branch formed by the stator winding 122 and the rotor 121 connected in series, and the driving branch is electrically connected to the external power source in the driving state, and the external power source in the braking state
  • the brake branch includes a stator winding 122, a brake switch 163 and a branch formed by the electrical energy storage element 170 in series, the electrical energy storage element 170 is used to supply electrical energy to the brake branch, and the electrical energy storage element 170 is connected through the diode D3.
  • the stator winding 122 In the driving state, the stator winding 122 generates a first driving force for driving the rotation of the rotor 121.
  • the braking branch In the normal braking state, the braking branch is turned on, and the stator winding 122 generates a braking force that prevents the rotation of the rotor 121, and at the same time, the stator winding 122 A second driving force that drives the rotation of the rotor 121 is generated to resist or cancel a portion of the braking force.
  • the driving stator winding and the rotor itself are connected in a conductive manner. If a braking branch short circuit is detected in a certain period of time, the braking branch may not be cut off, and the stator winding and the rotor itself may be driven.
  • the driving force generated by the through connection can cancel the braking force generated by the brake branch.
  • the driving force generated by the driving branch is used in the braking state or the braking process to resist or cancel the braking force or braking force generated by the braking branch.
  • an independent anti-brake circuit or circuit may be used in the braking state or braking process to generate a positive force for resisting or canceling the braking reaction generated by the braking branch.
  • the control circuit comprises: a driving branch and a braking branch, the driving branch comprises a stator winding 122, a driving switch 150 and a branch formed by the rotor 121 in series, and the driving branch is electrically connected to the external power source in the driving state, in the braking state
  • the brake branch includes a stator winding 122, a second brake control switch 162, a brake switch 163 and a branch formed by the electrical energy storage element 170 in series, and the electrical energy storage element 170 is used for the brake branch Electrical energy is supplied, and the electrical energy storage element 170 is connected between the two ends of the rotor 121 through a diode D3.
  • the driving switch 150 turns on the connection of the stator winding 121 and the rotor 121 such that the stator winding 122 generates a driving force for driving the rotation of the rotor 121, and in the normal braking state, the driving switch 150 turns off the stator winding 122 and the rotor 121.
  • the second brake switch 162 and the brake switch 163 are both turned on, the brake branch is turned on, and the stator winding 122 provides the rotor 121 with a braking force that prevents its rotation. If the brake switch 163 has a short circuit fault, The dynamic control switch 162 is opened to cut off the conduction of the brake branch to avoid damage caused by excessive braking current.
  • a short circuit of the brake branch is detected for a period of time, the brake branch is cut off, and the connection between the stator winding of the drive branch and the rotor is turned on.

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Abstract

本发明公开了一种适用于电机的控制电路，包括驱动状态和制动状态，所述控制电路包括驱动状态和制动状态，所述驱动支路包括定子绕组和转子形成的支路，所述制动支路包括定子绕组、制动开关和电能存储元件形成的支路，所述电能存储元件用于为所述制动支路提供电能；在电机的制动状态下，若检测到所述制动支路发生短路，则驱动支路定子绕组和转子导通连接；同时，还公开了具有上述控制电路的电动工具，该控制电路能够在驱动状态退出后，进入制动状态使电机尽快停止转动，减小运动工作部件对人员的伤害几率；进一步能够在制动电流较大时，对制动支路进行控制，以防止急刹带来的安全隐患。

Description

适用于电机的控制电路和电动工具 技术领域
本发明涉及电机控制领域，尤其涉及一种适用于电机的控制电路以及包含该控制电路的电动工具。
背景技术
电机的主要作用是产生驱动转矩，为电器或各种机械的动力源，将电能转换为机械能。
在电动工具领域，电机被用于连接工作部件，以驱动工作部件进行动作以完成相应功能。当电动工具的操作开关闭合时，电动工具的电源与电机形成闭合的供电回路驱动电机工作，当操作开关打开时，虽然供电回路断开，但电机以及其所带动的工作部件因惯性的作用并不能立即结束动作，容易对操作者造成伤害。以角磨为例，该工具经常被用于切削和打磨，打磨盘是角磨的一种工作部件，当操作者松开操作开关后，希望能够尽快停止电机的转动，以避免高速旋转的打磨盘因人体误触或其他原因而造成伤害。
发明内容
为了实现上述目的，本发明采用如下的技术方案：
作为一种实施方式，一种适用于电机的控制电路，所述控制电路包括驱动状态和制动状态，所述电机包括定子绕组和转子，所述控制电路包括：
主控开关，所述主控开关闭合时，所述控制电路进入驱动状态，所述主控开关断开时，所述控制电路进入制动状态；
驱动支路，包括所述定子绕组、驱动开关和转子形成的支路，所述驱动开关用于控制所述定子绕组和转子之间连接的导通或切断；
制动支路，包括定子绕组、制动开关和电能存储元件形成的支路，所述电能存储元件用于为所述制动支路提供电能，所述电能存储元件设置在所述转子的两端之间；
控制单元，分别电连接所述主控开关、驱动开关和制动开关，控制所述主控开关、驱动开关和制动开关的闭合或打开；
其中，在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路定子绕组和转子导通连接。
进一步，所述电能存储元件与所述转子之间串联有二极管，以使电能存储元件进行单向充、放电。
进一步，所述驱动开关串联在所述定子绕组和转子之间，用于控制所述定子绕组和转子之间连接的导通或切断。
进一步，所述控制单元包括制动驱动电路，所述制动驱动电路在驱动状态下向所述制动开关发送脉冲信号，以控制所述制动开关的闭合或打开。
进一步，所述制动支路上还设置有电流检测单元，所述电流检测单元用于在制动状态下检测所述制动支路上的制动电流是否超过预设门限，若是，则所述控制电路控制所述制动开关处于打开状态，用于切断所述电能存储元件与定子绕组之间的导通。
进一步，在制动状态下，若所述制动支路上的制动电流超过预设门限，则所述控制电路控制驱动开关闭合，使所述定子绕组和转子之间的电流导通。
进一步，所述制动支路还包括第一制动控制开关和第二制动控制开关；自所述定子绕组的一端至其另一端，所述制动支路包括依次串联的所述第一制动控制开关、所述电能存储元件、所述制动开关和所述第二制动控制开关。
进一步，所述控制电路包括电压检测单元，所述电压检测单元用于在驱动状态下检测所述制动开关是否发生短路，若是，则所述控制电路控制所述第一制动控制开关和第二制动控制开关使所述制动支路在制动状态不导通。
进一步，在制动状态下，若所述制动支路上的制动电流超过预设门限，则所述控制电路控制第一制动控制开关和/或第二制动控制开关打开以切断所述制动支路的导通。
进一步，所述控制单元包括：第一电压检测单元、制动驱动电路、第一制动保护电路、第二制动保护电路和中央处理器，所述制动支路上还设置有第二电压检测单元；
所述第一电压检测单元用于在驱动状态下检测所述制动开关与所述第二制动控制开关连接点处的第一电压，并将所述第一电压发送给所述中央处理器；
所述第二电压检测单元设置在所述制动开关与所述电能储能元件之间，用于向所述第一制动保护电路输出第二电压；
所述中央处理器根据所述第一电压判断所述制动开关是否短路，进而控制所述制动支路在制动状态下是否导通；所述中央处理器在制动状态下向所述制动驱动电路发送脉冲信号；
所述第一制动保护电路根据所述第二电压向所述制动驱动电路输出第一保护信号或第二保护信号；当所述第一制动保护电路向所述制动驱动电路输出第一保护信号时，向所述第二制动保护电路输出第三保护信号；
所述制动驱动电路根据所述脉冲信号和第一保护信号生成第一驱动信号，所述第一驱动信号为控制所述制动开关周期性闭合的信号；所述制动驱动电路根据所述脉冲信号和第二保护信号生成第二驱动信号，所述第二驱动信号为控制所述制动开关打开的信号；
所述第二制动保护电路根据所述第三保护信号生成第四保护信号，所述第四保护信号为控制所述驱动开关关闭的信号。
进一步，所述第一制动保护电路采用自锁电路。
进一步，在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
相应地，本发明还提供了一种电动工具，包括壳体，所述壳体上设置有操作开关和工作部件，所述壳体内设置有用于驱动工作部件的电机，所述电动工具还包括上述任意一项所述适用于电机的控制电路。
进一步，所述电动工具为角磨，所述工作部件为打磨盘。
作为另一种实施方式，一种适用于电机的控制电路，所述电机包括定子绕组和转子，所述控制电路包括驱动支路和制动支路，所述控制电路包括驱动状态和制动状态，
所述驱动支路包括定子绕组和转子形成的支路；
所述制动支路包括定子绕组、制动开关和电能存储元件形成的支路，所述电能存储元件用于为所述制动支路提供电能；
在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路定子绕组和转子导通连接。
进一步，在制动状态下，驱动支路定子绕组和转子断开连接，检测到制动支路短路，切断制动支路，使得驱动支路定子绕组和转子导通连接。
进一步，所述定子绕组和转子之间设置有驱动开关，在制动状态下，若所述制动开关发生短路故障，所述驱动开关闭合以导通所述定子绕组和转子连接。
进一步，在驱动状态和制动状态下，所述电机的定子绕组和转子之间均导通连接。
进一步，所述制动支路上还设置有至少一个制动控制开关，若所述制动开关发生短路故障，则打开所述制动控制开关中的至少一个以切断所述制动支路。
进一步，所述电能存储元件与所述转子之间串联有二极管，以使电能存储元件进行单向充、放电。
进一步，所述控制电路包括制动电路，所述制动电路在制动状态下向所述制动开关发送脉冲信号，以控制所述制动开关的闭合或打开。
进一步，所述制动支路上还设置有电流检测单元，所述电流检测单元用于在制动状态下检测所述制动支路上的制动电流是否超过预设门限，若是，则打开所述制动开关以切断所述电能存储元件与定子绕组之间的导通。
进一步，在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
相应地，本发明还提供了一种电动工具，包括壳体，所述壳体上设置有操作开关和工作部件，所述壳体内设置有用于驱动工作部件的电机，所述电动工具还包括上述任意一项所述的适用于电机的控制电路。
进一步，所述电动工具为角磨，所述工作部件为打磨盘。
作为另一种实施方式，一种适用于电机的控制电路，所述电机包括定子绕组和转子，所述控制电路包括驱动支路和制动支路，所述控制电路包括驱动状 态和制动状态，
在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路导通。
进一步，所述驱动支路包括定子绕组和转子形成的支路；在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
进一步，在制动状态下，驱动支路定子绕组和转子断开连接，检测到制动支路短路，切断制动支路，使得驱动支路定子绕组和转子导通连接。
进一步，所述定子绕组和转子之间设置有驱动开关，在制动状态下，若所述制动开关发生短路故障，所述驱动开关闭合以导通所述定子绕组和转子连接。
进一步，在驱动状态和制动状态下，所述电机的定子绕组和转子之间均导通连接。
进一步，在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
相应地，本发明还提供了一种电动工具，包括壳体，所述壳体上设置有操作开关和工作部件，所述壳体内设置有用于驱动工作部件的电机，所述电动工具还包括上述任意一项所述的适用于电机的控制电路。
进一步，所述电动工具为角磨，所述工作部件为打磨盘。
本发明的有益之处在于，该适用于电机的控制电路以及包含该控制电路的电动工具能够在驱动状态退出后，促使电机的转子尽快停止转动，避免高速旋转的工作部件对操作者以及其他人员带来不必要的伤害；能够在制动状态下，对制动支路中的制动电流进行有效控制，避免因制动电流过大而导致定子绕组烧坏甚至出现急刹带来不必要的人员伤害。
附图说明
图1是作为实施例之一的角磨的结构示意图；
图2是适用于电机的控制电路的第一种电路图；
图3是图2中适用于电机的控制电路在驱动状态下的驱动电流路径示意图；
图4是图2中适用于电机的控制电路在驱动状态下的充电电流路径示意图；
图5是图2中适用于电机的控制电路在制动状态下的制动电流路径示意图；
图6是图2中适用于电机的控制电路在制动状态下的充电电流路径示意图；
图7是适用于电机的控制电路的第二种电路图；
图8是适用于电机的控制电路的第三种电路图；
图9是图8中控制电路的模块示意图；
图10为控制电路中第一电压检测单元的一种电路图；
图11为控制电路中第一制动保护电路的一种电路图；
图12为控制电路中第二制动保护电路的一种电路图；
图13是图8中适用于电机的控制电路的控制流程图；
图14是适用于电机的控制电路的第四种电路图；
图15是适用于电机的控制电路的第五种电路图；
图16是适用于电机的控制电路的第六种电路图。
具体实施方式
以下结合附图和具体实施例对本发明作具体的介绍。
为了方便说明，电动工具以一个角磨100作为实例，当然电动工具也可以是其它能将输出的扭矩转化为其他形式运动的工具，这些工具可能用来打磨工件，比如砂光机；这些工具也可能用来切割工件，比如往复锯、圆锯、曲线锯；这些工具也可能用来做冲击使用，比如电锤；这些工具也可能是园林类工具，比如修枝机和链锯；另外这些工具也可能作为其它用途，比如搅拌机。只要这些电动工具包括驱动其工作部件运动的电机120，即可采用以下披露的技术方案的实质内容。
图1所示的角磨100，包括：壳体，以及设置在壳体上的打磨盘110和操作开关140，在壳体内设置有电机120及其控制电路，以及自壳体内向外延伸的电源线缆130。打磨盘110，用于实现例如打磨或切割的工具功能，电机120在接通电源的情况下驱动打磨盘110工作。
电源线缆130，包括两个连接端子，用于接入电能为电机120供电。电源线缆130可接入直流电或交流电源。具体的，电源线缆130为交流插头，插入交流市电以接入电能为电机120供电；操作开关140为按压式操作开关140，档位式操作开关140或其他能够被用户操作的开关，该操作开关140设置在角磨100的外壳上可供用户操作的位置，当该操作开关140被用户触发时，电机的控制电路导通电机120与电源线缆130之间的供电路径；当操作开关140被用户释放时，电机的控制电路切断电机120与电源线缆130之间的供电路径。
电机120的输出轴上安装或固定打磨盘110，转子转动驱动输出轴转动，进而带动打磨盘110进行打磨或切割工作。需要说明的是，凡是能被转子驱动而转动的装置都被认为是本发明的输出轴。当操作开关140被用户释放时，转子在惯性的作用下仍带动打磨盘110转动，此时若对转子施加与其转动方向相反的制动力，则能够促使转子尽快停止转动，避免高速旋转的打磨盘110对操作者以及其他人员带来不必要的伤害。
作为实现上述目的的一种实施方式，图2中电机的控制电路包括主控开关151、驱动支路、制动支路和控制单元180；该控制电路包括驱动状态和制动状态，当主控开关151闭合时，控制电路为驱动状态，当主控开关151断开时，控制电路为制动状态。控制单元180检测到设置在工具外壳上的操作开关140被触发，则闭合主控开关151，控制电路处于驱动状态，控制单元180检测到操作开关140被释放，则打开主控开关151，控制电路处于制动状态。
主控开关151设置在驱动支路与外部电源之间的供电路径上，主控开关151闭合时，控制电路进入驱动状态，主控开关151打开时，控制电路进入制动状态。主控开关151的第一端与电源线缆130的第一电源端131电性连接，第二端与驱动支路的第一端电性连接，电源线缆130的第二电源端132与驱动支路的第二端电性连接，主控开关151被配置为建立和切断驱动支路与电源线缆130的电性电性连接。主控开关151导通时，其第一端和第二端导通，驱动支路与电源线缆130之间的电性连接建立；主控开关151断开时，其第一端与第二端断开，驱动支路与电源线缆130之间的电性连接切断。
上述电机可以采用串励电机、串激电机、并励电机、同步电机或异步电机等，本实施方式以串励电机或串激电机为例，包括定子绕组122和转子121，上 述驱动支路包括定子绕组122、驱动开关152和转子121串联形成的支路；上述制动支路包括定子绕组122、制动控制开关组和电能存储元件170串联形成的支路。
具体的，如图2所示，驱动开关152串接在定子绕组122和转子121之间形成驱动支路，定子绕组122的第一端作为驱动支路的第一端与主控开关151的第二端电性连接，定子绕组122的第二端与驱动开关152的第一端电性连接，驱动开关152的第二端与转子121的第一端电性连接，转子121的第二端作为驱动支路的第二端与电源线缆130的第二电源端132电性连接。在驱动状态下，驱动开关152闭合，定子绕组122和转子121之间导通，流经定子绕组122的电流使得定子绕组122产生驱动转子121转动的磁场，转子121转动带动输出轴转动，进而带动连接至输出轴一端的打磨盘110工作。其中，驱动开关152为功率器件中的一种，如MOS管、可控硅等。
制动控制开关组包括第一制动控制开关161和第二制动控制开关162，第一制动控制开关161的第一端与定子绕组122的第一端电性连接，第二端与电能存储元件170的第一端电性连接，电能存储元件170的第二端接地；第二制动控制开关162的第一端与定子绕组122的第二端电性连接，第二制动控制开关162的第二端与电能存储元件170的第二端之间电性连接，制动控制开关组、电能存储元件170、定子绕组122通过上述连接方式形成制动支路。第一制动控制开关161可以采用继电器、场效应管或晶闸管中的一种，第二制动控制开关162可以采用继电器、场效应管或晶闸管中的一种。
电能存储元件170为制动支路的电能来源，为了使得制动支路的制动电流方向稳定，电能存储元件170采用带极性的电容，并联在转子121的两端。因电能存储元件170采用带极性的电容，只能单方向充电、放电，电机120在交流电源中正常运转时，会产生方向周期性变化的感应电动势，因此在转子121的第一端与电能存储元件170的第一端之间串接有二极管D3，二极管D3的阴极与电能存储元件170的第一端之间电性连接，二极管D3的阳极与转子121的第一端电性连接以形成充电支路；二极管D3的加入能够保证变化的感应电动势只能在一个方向给电容充电，避免反方向充电损坏电容。电能存储元件170的两端还并联泄放电阻R，电能存储元件170和泄放电阻R构成放电回路以实现对电容的缓慢放电。
参考图3所示，对上述介绍电路的工作原理做进一步介绍，当设置在工具外 壳上的操作开关140被触发时，控制单元180检测到操作开关140由打开状态切换为闭合状态，控制主控开关151和驱动开关152闭合，电源线缆130接入驱动支路为电机120供电。假设第一电源端131为高压端，第二电源端132为低压端，则形成如图3中301所示电流路径，电流从电源经第一电源端131流经主控开关151，进入驱动支路，依次流经定子绕组122、驱动开关152、转子121，再由第二电源端132返回电源，从而驱动电机120工作。
参考图4所示，在驱动支路导通的同时，形成如401所示的充电支路电流路径，电流经第一电源端131流入，依次经主控开关151、定子绕组122、驱动开关152、电能储存元件170后回到第二电源端132，构成充电支路为电能存储元件170充电。
参考图5所示，当设置在工具外壳上的操作开关140由闭合状态切换为打开状态时，作为响应，控制单元180控制主控开关151和驱动开关152均处于打开状态，控制制动控制开关组中的第一制动控制开关161和第二制动控制开关162均处于闭合状态。此时，驱动支路与外部电源断开电性连接，无法继续为转子121提供驱动力；电能存储元件170作为制动支路的电能来源开始发挥作用，如501所示的制动电流路径，电流经电能存储元件170的第一端依次流经第一制动控制开关161、定子绕组122、第二制动控制开关162，再返回至电能存储元件170的第二端。定子绕组122因制动电流产生磁场，作用于转子121。与此同时，参考图6所示，随着电能存储元件170放电，转子121在制动电流产生的磁场中运动会产生电动势，当其产生的电动势高于电能存储元件170的电动势，则能够对电能存储元件170进行充电，转子121能量进一步被消耗；如图中601所示电流路径，电流经转子121的第一端依次流经二极管D3、电能存储元件170后返回转子121，当转子121中流经电流，定子绕组122中制动电流所产生的磁场便能够对其施加制动力，从而快速降低转子121的转速。
为避免因制动电流太大，而将定子绕组122击穿或烧坏，作为一种改进的实施方式，可在定子绕组122两端并联续流二极管D1、D2，二极管D1、D2的阳极均与第二制动控制开关162的第二端电性连接，续流二极管D1、D2的阴极均与第一制动控制开关161的第二端电性连接，通过续流二极管D1、D2和定子绕组122形成续流回路，使定子绕组122的电能在回路中以续流方式消耗，对从定子绕组122起到一定的保护作用。
由上述分析可知，控制电路在制动状态下所产生的制动电流比较大，如果持续导通制动支路的话，极易损坏定子绕组122，因此可以如图7所示，除了与上述控制电路相同的元器件及其连接关系，该实施方式中的控制电路还包括制动开关163，即在制动支路中增加制动开关163，制动开关163的第一端电性连接第二制动控制开关162的第二端，第二端电性连接电能存储元件170的第二端；制动开关163与控制单元180电性连接，控制单元180可以根据制动电流的大小控制制动开关163的通断以导通或者切断制动支路的制动电流回路，从而控制制动电流的大小。具体的，控制单元180可以向制动开关163发送脉冲信号以控制其周期性闭合或关闭，例如PWM信号，以实现对制动电流的占空比控制。具体的，制动开关163采用场效应晶体管中的一种，如IGBT。
鉴于上述描述，在制动状态下，制动开关163对制动支路中的制动电流控制起到了关键作用，因此，一旦制动开关163发生短路或者是控制单元180向其输出的脉冲信号发生异常(例如总是输出高电平)，使得制动支路在制动状态时一直处于导通状态，从而导致制动电流过大，出现急刹情况，以角磨100为例，极有可能导致磨盘110飞出来，伤害用户及其他人员。
对于制动开关163，其可能是在控制电路进入制动状态之前就发生短路故障，也有可能是在制动状态时发生短路故障，其两端的电压也会因所处状态不同出现不同的幅值或者幅值区间。当控制电路处于驱动状态时，制动支路不导通，如果制动开关163处发生短路，由于制动开关163的第二端接地，则其第一端处的电压被接地端拉低趋近于0，而其在正常情况下，可能为+5V(三极管集电极电压)。根据上述分析，可以在控制电路进入制动状态之前对制动开关163进行检测，如果制动开关163已经发生短路，则控制电路在操作开关140打开后，不再导通制动支路。
如果制动开关163在控制电路处于制动状态时发生短路故障或者是控制单元180发送的脉冲信号错误，例如控制单元180一直输出高电平，均容易导致制动电流变大，随着制动电流变大，可以通过设置电流检测单元用于制动支路上电流的检测，来实现对制动支路的控制；当制动电流变大，制动开关163的第二端处的电压也随之增加，所以也可以据此来设定电压门限来进行制动电流的判断，从而对制动支路进行进一步控制。
作为实现上述目的的一种实施方式，参考图8和图9所示，制动支路上还设置有第二电压检测单元190，第二电压检测单元190电性连接在制动开关163的第二端与地之间，用于在制动状态下检测制动开关163第二端处的电压。控制单元180包括中央处理器(MCU)181，第一电压检测单元182，制动驱动电路183和第一制动保护电路184；中央控制器181分别与第一电压检测单元182和制动驱动电路183电性连接；第二电压检测单元190和第一制动保护电路184电性连接(对应d节点)，第一制动保护电路184与制动驱动电路183电性连接。中央处理器181分别与主控开关151(对应a节点)、驱动开关152(对应b1节点)以及第一制动控制开关161(对应f节点)、第二制动控制开关162(对应g节点)电性连接；第一电压检测单元182与制动开关163的第一端(对应c节点)电性连接，制动驱动电路183与制动开关163电性连接(对应e节点)。
第一电压检测单元182用于检测制动开关163的第一端处的电压U1，中央处理器181根据第一电压检测单元182所检测的电压值判断制动开关163是否发生短路故障，若是，则制动支路在制动状态不导通，否则，正常导通；中央处理器181在制动状态下向制动驱动电路183发送脉冲信号，并发送给制动驱动电路183；第一制动保护电路185根据第二电压检测单元190的检测结果输出第一保护信号或第二保护信号，并将第一保护信号或第二保护信号发送给制动驱动电路183；制动驱动电路183根据中央处理器181发送的脉冲信号和第一保护信号生成第一驱动信号，所述第一驱动信号为控制制动开关163周期性闭合的信号；制动驱动电路183根据中央处理器181发送的脉冲信号和第二保护信号生成第二驱动信号，所述第二驱动信号为控制制动开关163打开的信号。
根据前述内容，当适用于电机的控制电路处于制动状态时，若中央处理器181所输出的脉冲信号发生异常，比如一直输出高电平信号，此时即使关闭制动开关163也无法对制动电流进行有效控制，为了避免这种情况发生，如图9所示，控制单元180可进一步包括第二制动保护电路185，第二制动保护电路185与第一制动保护电路184电性连接，与驱动开关152电性连接(对应b2节点)；当第一制动保护电路184向制动开关163输出第二保护信号的同时，向第二制动保护电路186输出第三保护信号，第二制动保护电路185根据第三保护信号生成第四保护信号，第四保护信号为控制驱动开关152关闭的信号。驱动开关152关闭后，定子绕组122中的制动电流一部分向下流过转子121，与转子121为电容充电的电流 部分抵消，从而起到减小制动电流的作用。
作为一种实施方式，图9中的第一电压检测单元182，可以采用图10所示的电路结构，该第一电压检测单元182包括两个串联的二极管D11和D12，二极管D11和D12的极性同向设置，二极管D11的阴极连接制动开关163的第一端(c节点)，二极管D11的阳极连接D12的阴极，D12的阳极一方面通过电阻R11和电容C11的串联电路接地，另一方面通过电阻R12接+5V直流电源。电阻R11和电容C11连接的一端(Braking_AD)连接中央处理器181，当电路未进入制动状态时，制动开关163在未短路的情况下，c点处的电压为高电平(开关的直流供电源一般为+5V)，此时二极管不导通，Braking_AD端输出的电压值U1为高电平信号；若制动开关163短路，则c点处的电压被接地端拉低，二极管D11、D12导通，Braking_AD端输出的电压值U1为低电平信号。中央处理器181可以根据预设的判断门限获知制动开关163是否短路。
根据上述介绍，在制动支路采取措施后，制动电流会减小，为了避免第二电压检测电路184检测到制动电流减小后，导致第一制动保护电路184再次向制动驱动开关183发送第一保护信号，即高电平信号，第一制动保护电路184可以采用自锁电路结构，即一旦当制动电流超过预设门限后，第一制动保护电路184将一直向制动开关163输出低电平信号。
作为一种实施方式，图9中的第一制动保护电路184，可以采用图11所示的电路结构，该第一制动保护电路184包括：三极管Q21和三极管Q22，电阻R21的第一端与二极管D21的阳极连接，另一端接+5V直流电源；二极管D21与电阻R22和电阻R23所形成的串联支路并联，二极管D21的阳极连接电阻R22的第一端，二极管D21的阴极连接电阻R23的第二端和第二电压检测单元190(节点d)，电阻R22的第二端一方面与电阻23的第一端连接，另一方面通过电容C21和电容C22形成的并联支路接地；三极管Q21为NPN型三极管，其基极通过电阻R24与电阻R22的第二端连接，发射极接地，集电极连接肖特基二极管D22的阴极，稳压二极管D22的阳极(protectl端)连接制动驱动电路183；三极管Q22为PNP型三极管，其基极一方面通过电阻R26连接三极管Q21的集电极，一方面通过电阻R25和电容C23的并联电路连接其自身的发射极，三极管Q22的集电极一方面通过电阻R27连接电阻R22的第二端，另一方面连接第二制动保护电路185。
在制动状态下，当制动支路的电流较小时，制动开关163第二端处的电压较小，第二电压检测单元190输出至第一制动保护电路的电压U2较小，三极管Q21不导通，protectl端向制动驱动保护电路183输出高电平信号，三极管Q22不导通，protect2端向第二制动保护电路输出低电平信号；当制动支路的电流较大时，制动开关163第二端处的电压U2较大，第二电压检测单元190输出至第一制动保护电路的电压较大，三极管Q21导通，protectl端向制动驱动保护电路183输出低电平信号，三极管Q22导通，protect2端向第二制动保护电路185输出高电平信号；在三极管Q22导通后，与其集电极上电阻R27相连的电阻R22的第二端处电压为高电平，此时，无论节点d处的电压为高电平还是低电平，三极管Q21均可以保持导通状态，实现自锁功能。
作为一种实施方式，图9中的第二制动保护电路185可以采用图12所示的电路结构，该第二制动保护电路185包括：PNP型三极管器Q31，三极管器Q31的集电极通过电阻R31连接驱动开关152(对应b2节点)，三极管器Q31的基极通过电阻R33与肖特基二极管D31连接三极管Q21的集电极(对应Pro_AD节点)，三极管Q31的发射极通过电阻R32与电容C31的并联电路与其基极连接，三极管Q31的发射极与三极管Q22的集电极连接(protect2节点)。
当第一制动保护电路184向第二制动保护电路185输出低电平信号时，Pro_AD节点为低电平信号，三极管Q31不导通，b2节点处输出低电平信号，控制驱动开关152打开；当第一制动保护电路184向第二制动保护电路185输出高电平信号时，Pro_AD节点为低电平信号，三极管Q31导通，b2节点处输出高电平信号，控制驱动开关152关闭。
以图13为例，对上述适用于电机的控制电路的控制过程做进一步解释，设定第一电压门限Vthl以及第二电压门限Vth2，在驱动状态下，当U1＞＝Vthl时，认为制动开关163未短路，否则，认为短路，在操作开关断开后制动支路在制动状态不导通；在制动状态下，当U2＞＝Vth2时，认为制动支路中的制动电流太大，需要采取措施减小制动电流。同时，为了便于描述，规定本发明中所有涉及到的开关在接收到高电平电压时则关闭，为低电平时则打开。参考图9和图10，当用户关闭设置在工具外壳上的操作开关时，中央处理器181检测到操作开关由打开状态切换为闭合状态，则打开制动控制开关组中的制动控制开关161、162和制动开关163，关闭主控开关151，控制电路进入驱动状态，关闭驱动开关152， 此时，驱动支路导通，制动支路不导通；第一电压检测单元182检测制动开关163第一端处的电压U1，并将检测结果发送给中央处理器181进行门限判断，当U1＞＝Vthl，则认为制动开关163正常；当用户打开工具外部的操作开关，中央处理器181检测到操作开关由关闭切换为打开状态，则打开主控开关151和驱动开关152，关闭制动控制开关161和162，中央处理器181向制动驱动电路183发送脉冲信号(周期性的高低电平信号)，第二电压检测单元190检测制动开关163处的电压U2并发送给第一制动保护电路184，当U2＜Vth2时，第一制动保护电路185向制动驱动电路183发送第一保护信号，第一保护信号为高电平信号，制动驱动电路183结合脉冲信号和第一保护信号生成第一驱动信号，即能够控制制动开关163周期性关闭和打开的脉冲信号；当U2＞＝Vth2时，第一制动保护电路184向制动驱动电路183发送第二保护信号，第二保护信号为低电平信号，制动驱动电路183结合脉冲信号和第二保护信号生成第二驱动信号，即能够控制制动开关163打开的低电平信号；同时，第一制动保护电路184向第二制动保护电路185输出第三保护信号，第三保护信号为高电平信号，第二制动保护电路185根据第三保护信号生成第四保护信号，即能够控制驱动开关152关闭的信号高电平信号，做到二次防护。
作为另一种实施方式，适用于电机的控制电路中第二制动保护电路186与第一制动控制开关161和/或第二制动控制开关162电性连接，当第一制动保护电路184向制动开关163输出第一保护信号的同时，向第二制动保护电路185输出第三保护信号，第二制动保护电路185根据第三保护信号生成第五保护信号，第五保护信号为控制第二制动保护电路185与第一制动控制开关161和/或第二制动控制开关162打开的信号。第一制动控制开关161和/或第二制动控制开关162打开后，制动支路无法继续导通，从而起到减小制动电流的作用。
作为另一种实施方式，也可以通过打开第一制动控制开关161和/或第二制动控制开关162以及关闭驱动开关152结合的方式实现对制动电流的控制。
在本发明的一个实施例中，在电机制动状态下，驱动支路定子绕组和转子本身断开连接；若某一时间段检测到制动支路短路，或当检测到制动状态或制动过程中的制动参数超过预定值，抑或当检测到制动支路产生的刹车力超过预定值，切断制动支路，导通驱动支路定子绕组和转子的连接，驱动支路所产生的驱动力可以抵消制动支路产生的制动力，此时因制动支路已切断，制动支路 产生的制动力为零。
在本发明的另一个实施例中，在电机制动状态下，驱动支路定子绕组和转子本身导通连接；若某一时间段检测到制动支路短路，或当检测到制动状态或制动过程中的制动参数超过预定值，抑或当检测到制动支路产生的刹车力超过预定值，可以不切断制动支路，驱动支路定子绕组和转子本身导通连接所产生的驱动力可以抵消制动支路产生的制动力。
总而言之，本发明提供一种适用于电机的控制电路，所述电机包括定子绕组和转子，所述控制电路包括驱动支路和制动支路，所述控制电路包括驱动状态和制动状态；在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路导通，驱动支路导通产生的驱动力用于抵制或抵消制动支路产生的制动力或刹车力。需要注意的是，这里驱动支路导通，可以是驱动电路连续导通，也可以是部分导通。在本发明的一个实施例中，通过调整占空比的方式，可以实现驱动电路的部分导通。
进一步地，所述驱动支路包括定子绕组和转子形成的支路，当检测到制动状态或制动过程的制动参数超过预定值或者制动支路产生的刹车力超过预定值时，驱动支路定子绕组和转子导通连接，驱动支路定子绕组和转子导通连接所产生的驱动力用于抵制或抵消制动支路产生的制动力或刹车力。
以下通过图14-图16加以具体说明。
如图14所示，该控制电路与图7、图8最主要的区别是，制动支路中只包含制动开关163，在上述各实施方式中介绍的对制动开关163的导通或切断的控制以及短路故障检测方式均适用于本实施方式。控制电路包括：驱动支路和制动支路，驱动支路包括定子绕组122、驱动开关152和转子121串联形成的支路，驱动支路在驱动状态下与外部电源导通，在制动状态下与外部电源切断；制动支路包括定子绕组122、制动开关163和电能存储元件170串联形成的支路，电能存储元件170用于为该制动支路提供电能，电能存储元件170通过二极管D3连接在转子121的两端之间。在驱动状态下，驱动开关150导通定子绕组121和转子121的连接，使得定子绕组122产生驱动转子121转动的第一驱动力，在正常制动状态下，驱动开关150断开定子绕组122和转子121的连接，制动支路导通，定子绕组122为转子121提供阻止其转动的制动力；若制动开关163发生短路故障，则驱 动开关150闭合以导通定子绕组122和转子121连接，使得定子绕组122再次产生驱动转子121转动的第二驱动力，以抵消其所产生制动支路上产生的制动力的一部分。换言之，在制动状态下，驱动支路定子绕组和转子本身断开连接，若某一时间段检测到制动支路短路，可以不切断制动支路，导通驱动支路定子绕组和转子的连接，驱动支路所产生的驱动力可以抵消制动支路产生的制动力。上述各实施方式中介绍的控制电路中其余元器件的功能同样适用于本实施方式，不再赘述。
当然，也可以让控制电路在制动状态以及驱动状态中，一直让定子绕组和转子处于导通状态，也就是如图15所示，去掉驱动支路中的驱动开关150，同样，在上述各实施方式中介绍的对制动开关163的导通或切断的控制以及短路故障检测方式均适用于本实施方式，上述各实施方式中介绍的控制电路中其余元器件的功能同样适用于本实施方式。控制电路包括：驱动支路和制动支路，驱动支路包括定子绕组122和转子121串联形成的支路，驱动支路在驱动状态下与外部电源导通，在制动状态下与外部电源切断；制动支路包括定子绕组122、制动开关163和电能存储元件170串联形成的支路，电能存储元件170用于为该制动支路提供电能，电能存储元件170通过二极管D3连接在转子121的两端之间。在驱动状态下，定子绕组122产生驱动转子121转动的第一驱动力，在正常制动状态下，制动支路导通，定子绕组122产生阻止转子121转动的制动力，同时，定子绕组122产生驱动转子121转动的第二驱动力，以抵制或抵消制动力的一部分。换言之，在制动状态下，驱动支路定子绕组和转子本身导通连接，若某一时间段检测到制动支路短路，可以不切断制动支路，驱动支路定子绕组和转子本身导通连接所产生的驱动力可以抵消制动支路产生的制动力。上述各实施方式中介绍的控制电路中其余元器件的功能同样适用于本实施方式，不再赘述。
需要注意的是，本发明上述实施例，在制动状态或制动过程中采用驱动支路产生的驱动力，用来抵制或抵消制动支路产生的制动力或刹车力。在本发明其他一些实施例中，也可以采用在制动状态或制动过程中采用独立的反制动回路或电路产生一个正向力，用来抵制或抵消制动支路产生的制动反向力。
如图16所示，该控制电路与图7、图8最主要的区别是，在图14的基础上，在制动支路中仅增加了第二制动控制开关162，同样，在上述各实施方式中介绍的对制动开关163的导通或切断的控制以及短路故障检测方式均适用于本实施 方式，上述各实施方式中介绍的控制电路中其余元器件的功能同样适用于本实施方式。控制电路包括：驱动支路和制动支路，驱动支路包括定子绕组122、驱动开关150和转子121串联形成的支路，驱动支路在驱动状态下与外部电源导通，在制动状态下与外部电源切断；制动支路包括定子绕组122、第二制动控制开关162、制动开关163和电能存储元件170串联形成的支路，电能存储元件170用于为该制动支路提供电能，电能存储元件170通过二极管D3连接在转子121的两端之间。在驱动状态下，驱动开关150导通定子绕组121和转子121的连接，使得定子绕组122产生驱动转子121转动的驱动力，在正常制动状态下，驱动开关150断开定子绕组122和转子121的连接，第二制动开关162和制动开关163均导通，制动支路导通，定子绕组122为转子121提供阻止其转动的制动力，若制动开关163发生短路故障，则制动控制开关162打开以切断制动支路的导通，避免因制动电流过大所带来的伤害。换言之，在电机制动状态下，驱动支路定子绕组和转子本身断开连接，若某一时间段检测到制动支路短路，切断制动支路。当然，也可以在制动支路中仅增加第一制动控制开关161，第一制动开关161的控制方式同第二制动控制开关162。当然，也可以在制动开关163发生短路故障时打开第二制动控制开关162，关闭驱动开关150，换言之，在电机制动状态下，驱动支路定子绕组和转子本身断开连接，若某一时间段检测到制动支路短路，切断制动支路，导通驱动支路定子绕组和转子的连接。上述各实施方式中介绍的控制电路中其余元器件的功能同样适用于本实施方式，不再赘述。
以上显示和描述了本发明的基本原理、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发明，凡采用等同替换或等效变换的方式所获得的技术方案，均落在本发明的保护范围内。

Claims (33)

  1. 一种适用于电机的控制电路，所述控制电路包括驱动状态和制动状态，所述电机包括定子绕组和转子，所述控制电路包括：
    主控开关，所述主控开关闭合时，所述控制电路进入驱动状态，所述主控开关断开时，所述控制电路进入制动状态；
    驱动支路，包括所述定子绕组、驱动开关和转子形成的支路，所述驱动开关用于控制所述定子绕组和转子之间连接的导通或切断；
    制动支路，包括定子绕组、制动开关和电能存储元件形成的支路，所述电能存储元件用于为所述制动支路提供电能，所述电能存储元件设置在所述转子的两端之间；
    控制单元，分别电连接所述主控开关、驱动开关和制动开关，控制所述主控开关、驱动开关和制动开关的闭合或打开；
    其中，在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路定子绕组和转子导通连接。
  2. 根据权利要求1所述的适用于电机的控制电路，其特征在于，所述电能存储元件与所述转子之间串联有二极管，以使电能存储元件进行单向充、放电。
  3. 根据权利要求1所述的适用于电机的控制电路，其特征在于，所述驱动开关串联在所述定子绕组和转子之间，用于控制所述定子绕组和转子之间连接的导通或切断。
  4. 根据权利要求1所述的适用于电机的控制电路，其特征在于，所述控制单元包括制动驱动电路，所述制动驱动电路在驱动状态下向所述制动开关发送脉冲信号，以控制所述制动开关的闭合或打开。
  5. 根据权利要求1所述的适用于电机的控制电路，其特征在于，所述制动 支路上还设置有电流检测单元，所述电流检测单元用于在制动状态下检测所述制动支路上的制动电流是否超过预设门限，若是，则所述控制电路控制所述制动开关处于打开状态，用于切断所述电能存储元件与定子绕组之间的导通。
  6. 根据权利要求1所述的适用于电机的控制电路，其特征在于，在制动状态下，若所述制动支路上的制动电流超过预设门限，则所述控制电路控制驱动开关闭合，使所述定子绕组和转子之间的电流导通。
  7. 根据权利要求1所述的适用于电机的控制电路，其特征在于，所述制动支路还包括第一制动控制开关和第二制动控制开关；自所述定子绕组的一端至其另一端，所述制动支路包括依次串联的所述第一制动控制开关、所述电能存储元件、所述制动开关和所述第二制动控制开关。
  8. 根据权利要求7所述的适用于电机的控制电路，其特征在于，所述控制电路包括电压检测单元，所述电压检测单元用于在驱动状态下检测所述制动开关是否发生短路，若是，则所述控制电路控制所述第一制动控制开关和第二制动控制开关使所述制动支路在制动状态不导通。
  9. 根据权利要求7所述的适用于电机的控制电路，其特征在于，在制动状态下，若所述制动支路上的制动电流超过预设门限，则所述控制电路控制第一制动控制开关和/或第二制动控制开关打开以切断所述制动支路的导通。
  10. 根据权利要求7所述的适用于电机的控制电路，其特征在于，所述控制单元包括：第一电压检测单元、制动驱动电路、第一制动保护电路、第二制动保护电路和中央处理器，所述制动支路上还设置有第二电压检测单元；
    所述第一电压检测单元用于在驱动状态下检测所述制动开关与所述第二制动控制开关连接点处的第一电压，并将所述第一电压发送给所述中央处理器；
    所述第二电压检测单元设置在所述制动开关与所述电能储能元件之间，用于向所述第一制动保护电路输出第二电压；
    所述中央处理器根据所述第一电压判断所述制动开关是否短路，进而控制所述制动支路在制动状态下是否导通；所述中央处理器在制动状态下向所述制动驱动电路发送脉冲信号；
    所述第一制动保护电路根据所述第二电压向所述制动驱动电路输出第一保护信号或第二保护信号；当所述第一制动保护电路向所述制动驱动电路输出第一保护信号时，向所述第二制动保护电路输出第三保护信号；
    所述制动驱动电路根据所述脉冲信号和第一保护信号生成第一驱动信号，所述第一驱动信号为控制所述制动开关周期性闭合的信号；所述制动驱动电路根据所述脉冲信号和第二保护信号生成第二驱动信号，所述第二驱动信号为控制所述制动开关打开的信号；
    所述第二制动保护电路根据所述第三保护信号生成第四保护信号，所述第四保护信号为控制所述驱动开关关闭的信号。
  11. 根据权利要求10所述的适用于电机的控制电路，其特征在于，所述第一制动保护电路采用自锁电路。
  12. 根据权利要求1所述的适用于电机的控制电路，其特征在于，在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
  13. 一种电动工具，包括壳体，所述壳体上设置有操作开关和工作部件，所述壳体内设置有用于驱动工作部件的电机，其特征在于，所述电动工具还包括如权利要求1至12中上述任意一项所述适用于电机的控制电路。
  14. 根据权利要求13所述的电动工具，所述电动工具为角磨，所述工作部件为打磨盘。
  15. 一种适用于电机的控制电路，所述电机包括定子绕组和转子，所述控制电路包括驱动支路和制动支路，所述控制电路包括驱动状态和制动状态，其特征在于：
    所述驱动支路包括定子绕组和转子形成的支路；
    所述制动支路包括定子绕组、制动开关和电能存储元件形成的支路，所述电能存储元件用于为所述制动支路提供电能；
    在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路定子绕组和转子导通连接。
  16. 根据权利要求15所述的控制电路，其特征在于，在制动状态下，驱动支路定子绕组和转子断开连接，检测到制动支路短路，切断制动支路，使得驱动支路定子绕组和转子导通连接。
  17. 根据权利要求15所述的控制电路，其特征在于，所述定子绕组和转子之间设置有驱动开关，在制动状态下，若所述制动开关发生短路故障，所述驱动开关闭合以导通所述定子绕组和转子连接。
  18. 根据权利要求15所述的控制电路，其特征在于，在驱动状态和制动状态下，所述电机的定子绕组和转子之间均导通连接。
  19. 根据权利要求15所述的控制电路，其特征在于，所述制动支路上还设置有至少一个制动控制开关，若所述制动开关发生短路故障，则打开所述制动控制开关中的至少一个以切断所述制动支路。
  20. 根据权利要求15所述的控制电路，其特征在于，所述电能存储元件与 所述转子之间串联有二极管，以使电能存储元件进行单向充、放电。
  21. 根据权利要求15所述的控制电路，其特征在于，所述控制电路包括制动电路，所述制动电路在制动状态下向所述制动开关发送脉冲信号，以控制所述制动开关的闭合或打开。
  22. 根据权利要求15所述的控制电路，其特征在于，所述制动支路上还设置有电流检测单元，所述电流检测单元用于在制动状态下检测所述制动支路上的制动电流是否超过预设门限，若是，则打开所述制动开关以切断所述电能存储元件与定子绕组之间的导通。
  23. 根据权利要求15所述的适用于电机的控制电路，其特征在于，在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
  24. 一种电动工具，包括壳体，所述壳体上设置有操作开关和工作部件，所述壳体内设置有用于驱动工作部件的电机，其特征在于，所述电动工具还包括如权利要求15至23中任意一项所述的适用于电机的控制电路。
  25. 根据权利要求24所述的电动工具，其特征在于，所述电动工具为角磨，所述工作部件为打磨盘。
  26. 一种适用于电机的控制电路，所述电机包括定子绕组和转子，所述控制电路包括驱动支路和制动支路，所述控制电路包括驱动状态和制动状态，其特征在于：
    在制动状态下，若检测到所述制动支路的制动参数超过预定值，则驱动支路导通。
  27. 根据权利要求26所述的控制电路，其特征在于，所述驱动支路包括定 子绕组和转子形成的支路；在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
  28. 根据权利要求26所述的控制电路，其特征在于，在制动状态下，驱动支路定子绕组和转子断开连接，检测到制动支路短路，切断制动支路，使得驱动支路定子绕组和转子导通连接。
  29. 根据权利要求26所述的控制电路，其特征在于，所述定子绕组和转子之间设置有驱动开关，在制动状态下，若所述制动开关发生短路故障，所述驱动开关闭合以导通所述定子绕组和转子连接。
  30. 根据权利要求26所述的控制电路，其特征在于，在驱动状态和制动状态下，所述电机的定子绕组和转子之间均导通连接。
  31. 根据权利要求26所述的适用于电机的控制电路，其特征在于，在制动状态下，若检测到所述制动支路产生的刹车力超过预定值，则驱动支路定子绕组和转子导通连接。
  32. 一种电动工具，包括壳体，所述壳体上设置有操作开关和工作部件，所述壳体内设置有用于驱动工作部件的电机，其特征在于，所述电动工具还包括如权利要求26至31中任意一项所述的适用于电机的控制电路。
  33. 根据权利要求32所述的电动工具，其特征在于，所述电动工具为角磨，所述工作部件为打磨盘。
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