Method, device and active short-circuit protection circuit for protecting an electric machine

Abstract

The embodiment of the application discloses a kind of motor protection method, device and active short-circuit protection circuit, method includes: obtaining the working state of motor to be controlled, judge whether to need to carry out active short-circuit protection;If yes, then judge whether the active short-circuit protection circuit of motor to be controlled exists fault;If the result of judgment is that there is a fault, then control protection switch unit in active short-circuit protection circuit conduction.This application increases protection switch unit in active short-circuit protection circuit, and controls protection switch unit intervention when judging that active short-circuit protection circuit appears fault, solves the technical problem that once active short-circuit protection circuit appears fault in prior art, and cannot provide active short-circuit protection for motor, realizes the technical effect that provides multiple possibilities for active short-circuit protection, makes it more safe and reliable.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method, device and active short-circuit protection circuit for motors. Background Technology

[0002] Active short-circuit mode provides a safe fault handling method for high-speed vehicles equipped with permanent magnet synchronous motor systems. This method can avoid excessive back electromotive force after high voltage power failure, which could damage components and generate braking torque to accelerate the vehicle to a stop.

[0003] Existing active protection circuit configurations are as follows: Figure 1 As shown, turning off switches G1, G2, and G3, and turning on switches G4, G5, and G6, achieves an active short circuit to motor M; conversely, the reverse is also true. Switch T1 and the power supply are the power supply components for the controller. However, Figure 1 The circuit shown in the diagram can perform active short circuit protection only if the upper bridge arms G1 to G3 are fault-free or the lower bridge arms G4 to G6 are fault-free. If the conditions are not met, active short circuit protection cannot be performed. Summary of the Invention

[0004] This invention provides a method, device, and active short-circuit protection circuit for motors, solving the technical problem that in the prior art, the active short-circuit protection circuit cannot provide active short-circuit protection for the motor once it fails.

[0005] This invention provides a method for protecting a motor, the method comprising:

[0006] Obtain the operating status of the motor under control and determine whether active short-circuit protection is required;

[0007] If so, determine whether the active short-circuit protection circuit of the motor under control is faulty;

[0008] If the judgment result indicates that a fault exists, the protection switch unit in the active short-circuit protection circuit is turned on.

[0009] Furthermore, determining whether the active short-circuit protection circuit of the controlled motor has a fault includes:

[0010] Determine whether the active short-circuit protection circuit is faulty;

[0011] If the active short-circuit protection circuit is faulty, it is further determined whether the faulty transistor unit exists in the same bridge arm.

[0012] Furthermore, if the determination result indicates the existence of a fault, controlling the protective switch unit in the active short-circuit protection circuit to conduct includes:

[0013] If the judgment result is that the active short-circuit protection circuit has a fault, and the fault transistor unit does not exist in the same bridge arm, the protection switch unit is controlled to be turned on.

[0014] Further, the method further comprises:

[0015] If the judgment result is that the active short-circuit protection circuit has no fault, the protection switch unit is kept turned off.

[0016] Further, the active short-circuit protection circuit is a three-phase bridge rectifier circuit, and the active short-circuit protection circuit comprises a power supply unit, the protection switch unit and a transistor unit.

[0017] The power supply unit is electrically connected with the transistor unit, and the protection switch unit is electrically connected with the power supply unit and the transistor unit respectively.

[0018] Further, the protection switch unit is an insulated gate bipolar transistor.

[0019] The embodiment of the application further provides a protection device of a motor, and the device comprises:

[0020] A first judgment unit is used to acquire the working state of a motor to be controlled and judge whether active short-circuit protection is needed.

[0021] A second judgment unit is used to judge whether the active short-circuit protection circuit of the motor to be controlled has a fault if the judgment result of the first judgment unit is yes.

[0022] A switch control unit is used to control the protection switch unit in the active short-circuit protection circuit to be turned on if the judgment result of the second judgment unit is that there is a fault.

[0023] The embodiment of the application further provides an active short-circuit protection circuit, which comprises a power supply unit, a protection switch unit and a transistor unit; the transistor unit comprises a first transistor unit, a second transistor unit, a third transistor unit, a fourth transistor unit, a fifth transistor unit and a sixth transistor unit.

[0024] The power supply unit is connected in parallel with the protection switch unit.

[0025] The first transistor unit and the fourth transistor unit are connected in series and form a first transistor group; the second transistor unit and the fifth transistor unit are connected in series and form a second transistor group; the third transistor unit and the sixth transistor unit are connected in series and form a third transistor group; the first transistor group, the second transistor group, the third transistor group and the protection switch unit are connected in parallel.

[0026] The three-phase connection lines of the motor to be controlled are connected to the connection points between the first transistor unit and the fourth transistor unit, the connection points between the second transistor unit and the fifth transistor unit, and the connection points between the third transistor unit and the sixth transistor unit, respectively.

[0027] Further, the power supply unit comprises a first switch and a power supply source, and the first switch and the power supply source are connected in series.

[0028] The embodiment of the application further provides a motor controller, which comprises the motor protection device in any of the above embodiments.

[0029] The embodiment of the application discloses a motor protection method and device and an active short-circuit protection circuit, and the method comprises the following steps: acquiring the working state of a motor to be controlled, judging whether active short-circuit protection is needed, if yes, judging whether a fault exists in the active short-circuit protection circuit of the motor to be controlled, and if the result of the judgment is that a fault exists, controlling the protection switch unit in the active short-circuit protection circuit to be turned on. The application adds a protection switch unit in the active short-circuit protection circuit, and controls the protection switch unit to intervene when it is judged that a fault exists in the active short-circuit protection circuit, so that the technical problem that the active short-circuit protection circuit cannot provide active short-circuit protection for the motor once a fault exists in the active short-circuit protection circuit in the prior art is solved, and the technical effect that multiple possibilities are provided for the active short-circuit protection and the active short-circuit protection is safer and more reliable is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a circuit diagram of an active short-circuit protection circuit in the prior art;

[0031] Figure 2 is a flowchart of a motor protection method provided by the embodiment of the application;

[0032] Figure 3 is a circuit diagram of an active short-circuit protection circuit provided by the embodiment of the application;

[0033] Figure 4 is a flowchart of another motor protection method provided by the embodiment of the application;

[0034] Figure 5 is a circuit diagram of an active short-circuit protection circuit in which one fault transistor unit exists and which is provided by the embodiment of the application;

[0035] Figure 6 is a circuit diagram of an active short-circuit protection circuit in which two fault transistor units exist and which is provided by the embodiment of the application;

[0036] Figure 7is a circuit diagram of a three-fault transistor unit existing in the active short-circuit protection circuit provided by the embodiment of the present application;

[0037] Figure 8 is a structural diagram of the protection device of the motor provided by the embodiment of the present application. DETAILED DESCRIPTION

[0038] The present application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0039] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the drawings are used to distinguish different objects, but not to limit a specific order. Each of the embodiments of the present application can be executed alone, and each of the embodiments can also be executed in combination with each other, and the embodiments of the present application do not specifically limit this.

[0040] Figure 2 is a flow chart of the protection method of the motor provided by the embodiment of the present application. Figure 3 is a circuit diagram of the active short-circuit protection circuit provided by the embodiment of the present application, which comprises Figure 3 It can be known that the active short-circuit protection circuit is a three-phase bridge rectifier circuit. As shown in Figure 2 The protection method of the motor specifically comprises the following steps:

[0041] S101, obtaining the working state of the controlled motor, and determining whether the active short-circuit protection needs to be performed.

[0042] Specifically, taking the controlled motor M as a permanent magnet synchronous motor as an example, when the permanent magnet synchronous motor is in the process of high-speed running, the motor controller needs to obtain the working state of the controlled motor at all times to determine whether it is in the emergency braking state or other fault state. If the above state exists, the active short-circuit protection circuit needs to be started to provide active short-circuit protection for the controlled motor M; if the active short-circuit protection circuit does not need to be started, step S104 is executed to keep the active short-circuit protection circuit inaction.

[0043] S102, if yes, determining whether the active short-circuit protection circuit of the controlled motor exists a fault.

[0044] Specifically, after it is determined that the active short-circuit protection circuit needs to be started to provide active short-circuit protection for the controlled motor M, it is further determined whether the active short-circuit protection circuit exists a fault. As shown in Figure 3 There are six groups of transistor units in the active short-circuit protection circuit, i.e. Figure 3The transistor units G1-G6 are shown in the figure, wherein each transistor unit comprises an IGBT (Insulated Gate Bipolar Transistor) and a diode connected in parallel with the IGBT, and the transistor units G1-G3 form an upper bridge arm of the active short-circuit protection circuit, and the transistor units G4-G6 form a lower bridge arm of the active short-circuit protection circuit.

[0045] In the process of judging whether the active short-circuit protection circuit has a fault, it is necessary to judge whether there is a faulty transistor unit in G1-G6, and in order to ensure that the active short-circuit protection for the motor M to be controlled can be realized, after judging that there is one or more faulty transistor units in G1-G6, it is further necessary to judge whether the faulty transistor units are in the same bridge arm, so as to ensure that the active short-circuit protection for the motor M to be controlled can still be ensured after the protection switch unit G7 is turned on.

[0046] S103, if the judgment result is that there is a fault, then the protection switch unit in the active short-circuit protection circuit is turned on.

[0047] Specifically, if the judgment result is that there is a fault and the faulty transistors are not in the same bridge arm, then the protection switch unit G7 in the active short-circuit protection circuit is turned on, and the active short-circuit protection for the motor M to be controlled is realized.

[0048] The application adds a protection switch unit in the active short-circuit protection circuit, and controls the protection switch unit to intervene when it is judged that the active short-circuit protection circuit has a fault, thereby solving the technical problem in the prior art that the active short-circuit protection cannot be provided for the motor once the active short-circuit protection circuit has a fault, and achieving the technical effects of providing multiple possibilities for the active short-circuit protection and making it more safe and reliable.

[0049] On the basis of the above technical solutions, Figure 4 is a flow chart of another protection method for a motor provided by an embodiment of the application, as shown in the figure, S102 specifically comprises: Figure 4

[0050] S401, judging whether the active short-circuit protection circuit has a fault.

[0051] Specifically, referring to Figure 3 and Figure 4 , if it is judged that the active short-circuit protection circuit has no fault, then step S105 is executed, and the protection switch unit G7 is kept in an off state.

[0052] S402, if the active short-circuit protection circuit has a fault, then it is further judged whether the faulty transistor units are in the same bridge arm.

[0053] Specifically, referring to​Figure 3 In the process of judging whether the active short-circuit protection circuit is faulty, it is necessary to judge whether the transistor units in G1-G6 are faulty, and in order to ensure that the active short-circuit protection of the motor M to be controlled can be realized, after judging that one or more transistor units in G1-G6 are faulty, it is further necessary to judge whether the transistor units that are faulty are in the same bridge arm, so as to ensure that the active short-circuit protection of the motor M to be controlled can still be ensured after the protection switch unit G7 is turned on. It is known that if the transistor units that are faulty are in the same bridge arm, step S106 is executed, and the active short-circuit protection of the motor to be controlled cannot be realized, and an alarm is issued.

[0054] Exemplarily, referring to Figure 3 , if three transistor units G1-G3 in the upper bridge arm fail at the same time, if the protection switch unit G7 is turned on at this time, G7 and the transistor units G4-G6 cannot form a loop to short-circuit the motor M to be controlled, and at this time the active short-circuit protection of the motor M to be controlled cannot be realized.

[0055] Optionally, if the judgment result is that there is a fault, the protection switch unit in the active short-circuit protection circuit is controlled to be turned on, comprising: if the judgment result is that the active short-circuit protection circuit has a fault, and the transistor units that are faulty are not in the same bridge arm, the protection switch unit is controlled to be turned on.

[0056] Specifically, when the judgment result is that the active short-circuit protection circuit has a fault, and the transistor units that are faulty are not in the same bridge arm, as shown in Figures 5-7 , which are schematic diagrams of one, two, and three faulty transistor units in the active short-circuit protection circuit, as shown in Figure 5 , the transistor units that are faulty are G4; as shown in Figure 6 , the transistor units that are faulty are G4 and G5; as shown in Figure 7 , the transistor units that are faulty are G3, G4, and G5, wherein Figure 7 the faulty transistor units in are not in the same bridge arm, at this time if the protection switch unit G7 is turned on, the active short-circuit protection circuit can still realize the active short-circuit protection of the motor M to be controlled.

[0057] Figure 5 Specifically, as shown in Figure 5 , the dashed arrow in Figure 6 clearly points out that when the transistor unit G4 fails, a loop to short-circuit the motor M to be controlled can be formed by the transistor unit G1-protection switch unit G7-transistor unit G5-transistor unit G6; as shown in Figure 6The dashed arrow in the figure indicates that when the transistor units G4 and G5 are faulty, only the transistor units G1, G2, G6 and the protection switch unit G7 need to be turned on to form a loop that short-circuits the motor M to be controlled; as shown in Figure 7 , when the transistor units G3, G4 and G5 of different bridge arms are faulty, only the transistor units G1, G2, G6 and the protection switch unit G7 need to be turned on to form a loop that short-circuits the motor M to be controlled.

[0058] Optionally, the motor protection method further includes: if the judgment result is that the active short-circuit protection circuit is not faulty, keeping the protection switch unit off.

[0059] Specifically, if the motor controller judges that the active short-circuit protection circuit is not faulty, the protection switch unit G7 does not need to be turned on, and only needs to be kept off, and the active short-circuit protection unit can be used normally to short-circuit the motor to be controlled.

[0060] Optionally, as shown in Figure 3 , the active short-circuit protection circuit includes a power supply unit 31, a protection switch unit G7 and a transistor unit 32; the power supply unit 31 is electrically connected with the transistor unit 32, and the protection switch unit G7 is electrically connected with the power supply unit 31 and the transistor unit 32 respectively.

[0061] Specifically, referring to Figure 3 , the power supply unit 31 can provide power for the transistor unit 32 and the protection switch unit G7, and the protection switch unit G7 can be turned on when the transistor unit 32 is faulty, so that the active short-circuit protection circuit can continue to work and ensure that the motor M to be controlled is short-circuited, wherein the fault in the transistor unit 32 means that the multiple transistor units that are faulty are not in the same bridge arm.

[0062] Preferably, referring to Figures 3-7 , the protection switch unit G7 is an insulated gate bipolar transistor.

[0063] Specifically, the protection switch unit G7 can be realized in the form of an insulated gate bipolar transistor IGBT in parallel with a diode, that is, the protection switch unit G7 is a standby transistor unit in the active short-circuit protection circuit, in addition, the protection switch unit G7 can also be other switching devices that can be turned on to ensure that the active short-circuit protection circuit continues to short-circuit the motor M to be controlled after a fault, which is not limited here.

[0064] Figure 8 is a structure diagram of a motor protection device provided by an embodiment of the application, as shown in Figure 8 , the motor protection device includes a first judgment unit 71, a second judgment unit 72 and a switch control unit 73, wherein:

[0065] The first judging unit 71 is configured to acquire the working state of the motor to be controlled and determine whether active short-circuit protection is needed.

[0066] The second judging unit 72 is configured to determine whether the active short-circuit protection circuit of the motor to be controlled has a fault if the result of the determination of the first judging unit is yes.

[0067] The switch control unit 73 is configured to control the protection switch unit in the active short-circuit protection circuit to be turned on if the result of the determination of the second judging unit is that there is a fault.

[0068] Optionally, the second judging unit 72 is specifically configured to:

[0069] determine whether the active short-circuit protection circuit has a fault.

[0070] If the active short-circuit protection circuit has a fault, further determine whether the faulty transistor unit is in the same bridge arm.

[0071] Optionally, the switch control unit 73 is specifically configured to:

[0072] If the result of the determination of the second judging unit 72 is that the active short-circuit protection circuit has a fault and the faulty transistor unit is not in the same bridge arm, control the protection switch unit to be turned on.

[0073] Optionally, the switch control unit 73 is further configured to:

[0074] If the result of the determination of the second judging unit 72 is that the active short-circuit protection circuit does not have a fault, keep the protection switch unit turned off.

[0075] The device provided by the embodiment of the application has the same implementation principle and technical effects as the foregoing method embodiment, and for brevity, the part not mentioned in the device embodiment can be referred to the corresponding content in the foregoing method embodiment.

[0076] The protection device for the motor provided by the embodiment of the application has the same technical features as the protection method for the motor provided by the foregoing embodiment, and can solve the same technical problem and achieve the same technical effect. The embodiment of the application further provides an active short-circuit protection circuit, as shown in the following table. Figures 3-7 The active short-circuit protection circuit includes a power supply unit 31, a protection switch unit G7, and a transistor unit 32; the transistor unit 32 includes a first transistor unit G1, a second transistor unit G2, a third transistor unit G3, a fourth transistor unit G4, a fifth transistor unit G5, and a sixth transistor unit G6.

[0077] The power supply unit 31 is connected in parallel with the protection switch unit G7.

[0078] The first transistor unit G1 and the fourth transistor unit G4 are connected in series and form a first transistor group; the second transistor unit G2 and the fifth transistor unit G5 are connected in series and form a second transistor group; the third transistor unit G3 and the sixth transistor unit G6 are connected in series and form a third transistor group; the first transistor group, the second transistor group, the third transistor group and the protection switch unit G7 are connected in parallel.

[0079] The three-phase connection lines of the motor to be controlled M are connected to the connection points between the first transistor unit G1 and the fourth transistor unit G4, the connection points between the second transistor unit G2 and the fifth transistor unit G5, and the connection points between the third transistor unit G3 and the sixth transistor unit G6, respectively.

[0080] Optionally, referring to Figures 3-7 The power supply unit 31 comprises a first switch T1 and a power supply V1; the first switch T1 and the power supply V1 are connected in series.

[0081] The motor controller provided by the embodiment of the present application is controlled by the motor controller in the above embodiment to realize the protection method of the motor in the above embodiment, so the motor controller provided by the embodiment of the present application also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0082] The embodiment of the present application further provides a motor controller, which comprises the motor protection device in any of the above embodiments.

[0083] The motor controller provided by the embodiment of the present application comprises the motor protection device in the above embodiment, so the motor controller provided by the embodiment of the present application also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0084] In the description of the embodiment of the present application, unless otherwise explicitly specified and limited, the terms “mounting”, “connection” and “linking” should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, and can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0085] Finally, it should be noted that the above merely describes the preferred embodiments of the present application and the principles of the technology applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, reconfigurations and substitutions can be made by those skilled in the art without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A method for protecting an electric motor, characterized in that, The method includes: Obtain the operating status of the motor under control and determine whether active short-circuit protection is required; If so, determine whether the active short-circuit protection circuit of the motor under control is faulty; If the judgment result indicates that a fault exists, the protection switch unit in the active short-circuit protection circuit is turned on to form a short-circuit loop with the fault-free transistor unit through the protection switch unit.

2. The method for protecting a motor according to claim 1, characterized in that, The determination of whether the active short-circuit protection circuit of the motor under control is faulty includes: Determine whether the active short-circuit protection circuit is faulty; If the active short-circuit protection circuit is faulty, it is further determined whether the faulty transistor unit exists in the same bridge arm.

3. The method for protecting a motor according to claim 2, characterized in that, If the determination result indicates that a fault exists, controlling the protection switch unit in the active short-circuit protection circuit to conduct includes: If the determination result indicates that the active short-circuit protection circuit is faulty, and the faulty transistor unit is not located in the same bridge arm, then the protection switch unit is controlled to turn on.

4. The method for protecting a motor according to claim 1, characterized in that, The method further includes: If the determination result is that there is no fault in the active short-circuit protection circuit, then the protection switch unit remains off.

5. The method for protecting a motor according to claim 1, characterized in that, The active short-circuit protection circuit includes a power supply unit, the protection switch unit, and a transistor unit; The power supply unit is electrically connected to the transistor unit, and the protection switch unit is electrically connected to both the power supply unit and the transistor unit.

6. The method for protecting a motor according to claim 5, characterized in that, The protection switch unit is an insulated gate bipolar transistor.

7. A protection device for an electric motor, characterized in that, The device includes: The first judgment unit is used to obtain the working status of the motor under control and determine whether active short-circuit protection is required. The second judgment unit is used to determine whether the active short-circuit protection circuit of the motor under control is faulty if the judgment result of the first judgment unit is yes. The switch control unit is used to control the protection switch unit in the active short-circuit protection circuit to conduct if the second judgment unit determines that a fault exists, so as to form a short-circuit loop with the non-faulty transistor unit through the protection switch unit.

8. An active short-circuit protection circuit, implementing the motor protection method according to any one of claims 1-6, characterized in that, The active short-circuit protection circuit includes a power supply unit, a protection switch unit, and a transistor unit; the transistor unit includes a first transistor unit, a second transistor unit, a third transistor unit, a fourth transistor unit, a fifth transistor unit, and a sixth transistor unit; The power supply unit is connected in parallel with the protection switch unit; The first transistor unit is connected in series with the fourth transistor unit to form a first transistor group; the second transistor unit is connected in series with the fifth transistor unit to form a second transistor group; the third transistor unit is connected in series with the sixth transistor unit to form a third transistor group; the first transistor group, the second transistor group, the third transistor group and the protection switch unit are all connected in parallel. The three interconnecting wires of the motor to be controlled are respectively connected to the connection point between the first transistor unit and the fourth transistor unit, the connection point between the second transistor unit and the fifth transistor unit, and the connection point between the third transistor unit and the sixth transistor unit.

9. The active short-circuit protection circuit according to claim 8, characterized in that, The power supply unit includes a first switch and a power supply; the first switch and the power supply are connected in series.

10. A motor controller, characterized in that, The motor controller includes the motor protection device described in claim 7.

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