Fault detection circuit of gardening tool and gardening tool

Abstract

The utility model provides a gardening tool fault detection circuit and a gardening tool, and is applied to the technical field of gardening tools. The executing mechanism is used for being driven to execute garden operation; the driving device is electrically connected with the direct-current power supply to form a power supply loop, works when the power supply loop is closed so as to drive the executing mechanism, and comprises a motor and a motor driving circuit; the power supply switch is connected to the power supply loop in series and used for opening or closing the power supply loop, the fault detection circuit is connected to the power supply loop in series and closes the power supply loop to output a detection signal when the power supply switch is opened, and the fault detection circuit outputs different detection signals in a fault state and a normal state of the motor driving circuit respectively. The operation state of the motor driving circuit can be identified through the detection signal, so that the fault of the motor driving circuit can be found in time, the safety of the direct-current power supply is ensured, and the safety and the service life of the gardening tool are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of garden tools, in particular to a fault detection circuit of a garden tool and the garden tool. BACKGROUND

[0002] The driving motor, also known as a motor or a motor, is widely used in various garden tools such as lawn mowers and sweepers due to its excellent electric energy-mechanical energy conversion efficiency.

[0003] In the prior art, the working process of the motor is controlled by a motor driving circuit, Figure 1 A typical motor driving circuit is shown, which includes six MOS (Metal-Oxide-Semiconductor) tubes. Among them, MOS tube Q1 and MOS tube Q2 are connected in series to form a first inverter bridge arm, MOS tube Q3 and MOS tube Q4 are connected in series to form a second inverter bridge arm, and MOS tube Q5 and MOS tube Q6 are connected in series to form a third inverter bridge arm. The three inverter bridge arms are connected in parallel to form an inverter circuit. The DC power supply P0 is connected to the motor driving circuit through the power supply switch K0. When the power supply switch K0 is closed, the DC power supply P0 outputs DC power. The motor driving circuit converts the DC power provided by the DC power supply P0 into AC power to drive the motor W1 to operate.

[0004] Under normal operation of the motor driving circuit, the two MOS tubes of any inverter bridge arm are alternately turned on. It can be understood that if the two MOS tubes of any inverter bridge arm are simultaneously turned on due to a fault, the DC power supply P0 is directly short-circuited, which further causes a fault of the DC power supply P0, and even endangers the safety of the garden tool. Therefore, how to accurately identify the operating state of the motor driving circuit and ensure the safety of the DC power supply has become one of the technical problems to be solved by those skilled in the art. Utility model content

[0005] Therefore, the present application is committed to providing a fault detection circuit of a garden tool and the garden tool, which accurately identifies the operating state of the motor driving circuit, ensures the safety of the DC power supply, and further improves the safety and service life of the garden tool.

[0006] In a first aspect, the present application provides a fault detection circuit of a garden tool, the garden tool comprising:

[0007] a DC power supply;

[0008] an actuator for being driven to perform a garden work;

[0009] a driving device electrically connected with the DC power supply to form a power supply loop and working to drive the actuator when the power supply loop is closed, the driving device comprising a motor and a motor driving circuit;

[0010] a power supply switch connected in series with the power supply circuit to open or close the power supply circuit;

[0011] the fault detection circuit is connected in series with the power supply circuit and closes the power supply circuit to output a detection signal when the power supply switch is opened, wherein the fault detection circuit outputs different detection signals in a fault state and a normal state of the motor drive circuit, respectively.

[0012] In an alternative embodiment, the fault detection circuit comprises:

[0013] a pre-charge circuit connected in parallel with the power supply switch, the pre-charge circuit closing the power supply circuit and limiting the current of the power supply circuit when the power supply switch is opened;

[0014] a detection circuit connected to the motor drive circuit to detect an electrical parameter of the motor drive circuit and output the detection signal when the pre-charge circuit closes the power supply circuit.

[0015] In an alternative embodiment, the pre-charge circuit comprises:

[0016] a pre-charge switch, one end of the pre-charge switch being connected to one end of the power supply switch;

[0017] a pre-charge resistor, one end of the pre-charge resistor being connected to the other end of the pre-charge switch, and the other end of the pre-charge resistor being connected to the other end of the power supply switch.

[0018] In an alternative embodiment, the detection circuit comprises:

[0019] a first voltage detection circuit connected to the motor drive circuit to detect an operating voltage of the motor drive circuit and output a first voltage detection signal.

[0020] In an alternative embodiment, the first voltage detection circuit comprises:

[0021] a first voltage dividing resistor, one end of the first voltage dividing resistor being connected to a positive terminal of the motor drive circuit;

[0022] a second voltage dividing resistor, one end of the second voltage dividing resistor being connected to the other end of the first voltage dividing resistor, and the other end of the second voltage dividing resistor being connected to a negative terminal of the motor drive circuit.

[0023] In an alternative embodiment, the detection circuit further comprises:

[0024] The second voltage detection circuit is connected with the DC power supply to detect the power supply voltage of the DC power supply and output a second voltage detection signal.

[0025] In an alternative embodiment, the second voltage detection circuit comprises:

[0026] The third voltage dividing resistor has one end connected with the positive terminal of the DC power supply;

[0027] The fourth voltage dividing resistor has one end connected with the other end of the third voltage dividing resistor and the other end connected with the negative terminal of the DC power supply.

[0028] In an alternative embodiment, the detection circuit comprises:

[0029] The current detection circuit is connected in series between the DC power supply and the motor drive circuit to detect the working current of the motor drive circuit and output a current detection signal.

[0030] In an alternative embodiment, the pre-charge switch comprises any one of an insulated gate bipolar transistor, a gate turn-off thyristor, a power transistor, a silicon controlled switch and a silicon carbide metal oxide switch.

[0031] In a second aspect, the present application provides a garden tool comprising:

[0032] A DC power supply;

[0033] An actuator for being driven to perform a garden work;

[0034] A drive device electrically connected with the DC power supply to form a power supply loop and work to drive the actuator when the power supply loop is closed, the drive device comprising a motor and a motor drive circuit;

[0035] A power supply switch connected in series with the power supply loop to disconnect or close the power supply loop;

[0036] The garden tool further comprises:

[0037] A fault detection circuit connected in series with the power supply loop and closing the power supply loop when the power supply switch is disconnected to output a detection signal, wherein the fault detection circuit outputs different detection signals in a fault state and a normal state of the motor drive circuit respectively.

[0038] Based on the above, the application provides a fault detection circuit of a garden tool, the garden tool comprising a direct current power supply; an actuator for being driven to perform garden work; a driving device electrically connected with the direct current power supply to form a power supply loop, and working to drive the actuator when the power supply loop is closed, and the driving device comprising a motor and a motor driving circuit; a power supply switch connected in series in the power supply loop to disconnect or close the power supply loop, the fault detection circuit being connected in series in the power supply loop, and closing the power supply loop to output a detection signal when the power supply switch is disconnected, and the fault detection circuit outputting different detection signals in a fault state and a normal state of the motor driving circuit respectively, so that the running state of the motor driving circuit can be identified through the detection signal output by the fault detection circuit, so that the fault of the motor driving circuit can be found in time, the safety of the direct current power supply is ensured, and the safety and service life of the garden tool are improved. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0040] Figure 1 is a circuit topology diagram of a motor driving circuit in the prior art.

[0041] Figure 2 is a structural schematic diagram of a garden tool provided by the present application.

[0042] Figure 3 is a structural schematic diagram of a fault detection circuit provided by the present application.

[0043] Figure 4 is a circuit topology diagram of a fault detection circuit provided by the present application.

[0044] Figure 5 is a circuit topology diagram of another fault detection circuit provided by the present application.

[0045] Figure 6 is a circuit topology diagram of still another fault detection circuit provided by the present application.

[0046] Figure 7 is a circuit topology diagram of still another fault detection circuit provided by the present application.

[0047] Figure 8 is a circuit topology diagram of still another fault detection circuit provided by the present application. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0049] As described above, the motor driving circuit includes three parallel inverter bridge arms, each of which includes two MOS tubes in series. In the normal operation of the motor driving circuit, the two MOS tubes of any inverter bridge arm are alternately turned on. In the operation process, if the two MOS tubes of any inverter bridge arm are simultaneously turned on due to failure, the direct current power supply P0 is directly short-circuited, thereby causing failure of the direct current power supply P0, and even endangering the safety of the garden tool.

[0050] To solve the above problems, the present application provides a fault detection circuit, which outputs different detection signals in the fault state and the normal state of the motor driving circuit respectively. The operation state of the motor driving circuit can be identified through the detection signals output by the fault detection circuit, so that the failure of the motor driving circuit can be found in time, the safety of the direct current power supply is ensured, and the safety and service life of the garden tool are improved.

[0051] The fault detection circuit provided by the present application is applied to a garden tool. In actual application, the garden tool can be a mowing robot, a cleaning robot, a robot for pesticide spraying, and a robot for sowing or branch building and other garden operations. Of course, it can also include other automated garden tools that drive the motor to operate through the motor driving circuit and then drive the actuator to work. Here, they are not listed one by one, and as long as they do not exceed the core idea of the present application, they also belong to the protection scope of the present application.

[0052] Referring to Figure 2 The garden tool described in the present application includes a direct current power supply 10, a driving device 20, an actuator 30, and a power supply switch K0. The driving device 20 includes a motor driving circuit 21 and a motor W1.

[0053] Referring to Figure 2 The direct current power supply 10 is connected to the driving device 20 to form a power supply loop. Specifically, the direct current power supply 10 is connected to the direct current side of the motor driving circuit 21, and the alternating current side of the motor driving circuit 21 is connected to the power supply port of the motor W1. As described above, the motor driving circuit 21 is used to convert the direct current provided by the direct current power supply 10 into alternating current and output to the motor W1 to drive the motor W1 to operate. The specific structure of the motor driving circuit 21 can be seen in Figure 2 and the foregoing related content, which will not be described in detail here.

[0054] The power supply switch K0 is connected in series in a power supply loop formed by the DC power supply 10 and the driving device 20. In the application scenario shown in the figure, one end of the power supply switch K0 is connected to the DC power supply 10, and the other end is connected to the DC side of the motor driving circuit 21. Figure 2 Figure 2 Based on the connection relationship shown in the figure, when the power supply switch K0 is closed, the DC power supply 10 is connected to the driving device 20, and the power supply loop is turned on. Correspondingly, when the power supply switch K0 is opened, the DC loop 10 is disconnected from the driving device 20.

[0055] The motor W1 is connected to the actuator 30, and when the motor W1 operates, the actuator 30 can be driven to perform garden work. It can be understood that the specific implementation of the actuator 30 will be different due to the different functions of the garden tool, for example, if the garden tool is a lawn mowing robot, the actuator 30 can be a lawn mowing tool that rotates under the drive of the motor W1, thereby completing the mowing work under the drive of the motor W1. For example, if the garden tool is a snow sweeping robot, the actuator 30 can be a cleaning tool, thereby performing the snow sweeping work under the drive of the motor W1. The implementation of the actuator 30 is not limited in the present application, and can be implemented according to related technologies, which will not be described in detail here.

[0056] The fault detection circuit 40 provided by the present application is also connected in series in the power supply loop formed by the DC power supply 10 and the driving device 20. When the power supply switch K0 is opened, the fault detection circuit 40 closes the power supply loop, so that the DC power supply 10 can supply power to the driving device 20 through the fault detection circuit 40. At the same time, the fault detection circuit 40 detects the motor driving circuit 21 and outputs corresponding detection signals. More importantly, the fault detection circuit 40 outputs different detection signals in the fault state and the normal state of the motor driving circuit 21, for example, the fault detection circuit 40 outputs a first detection signal in the fault state of the motor driving circuit 21, and correspondingly, a second detection signal in the normal state of the motor driving circuit 21. Based on this, the first detection signal can represent that the motor driving circuit 21 is in a fault state, and the second detection signal can represent that the motor driving circuit 21 is in a normal state.

[0057] ​As a typical application scenario, the power-on detection of the motor driving circuit 21 can be realized by the fault detection circuit provided in the application. In actual application, after the garden tool is powered off, the power supply switch K0 is in an open state. In response to the power-on operation of the garden tool, the fault detection circuit 210 closes the aforementioned power supply loop (at this time, the power supply switch K0 is still in an open state), and the direct current power supply 10 can supply power to the motor driving circuit 21 through the fault detection circuit 210. At the same time, the motor driving circuit 21 is detected by the fault detection circuit 210 provided in the application, and different detection signals are output to represent the detection results of the motor driving circuit 21. It can be understood that in the case that the detection signal represents that the motor driving circuit 21 is in a normal state, the power supply switch K0 can be continuously controlled to be turned on. Correspondingly, in the case that the detection signal represents that the motor driving circuit 21 is in an abnormal state, the current starting process can be stopped, so as to avoid the further expansion of the fault caused by the abnormal motor driving circuit 21, and affect the safe operation of the direct current power supply 10.

[0058] In summary, the fault detection circuit provided in the application is connected in series with the power supply loop, and the power supply loop is closed to output a detection signal when the power supply switch is opened. Moreover, the fault detection circuit outputs different detection signals in the fault state and the normal state of the motor driving circuit, respectively. The running state of the motor driving circuit can be identified through the detection signal output by the fault detection circuit, so as to timely discover the fault of the motor driving circuit, ensure the safety of the direct current power supply, and help to improve the safety and service life of the garden tool.

[0059] Based on the above core idea, the application also provides various optional implementation modes of the fault detection circuit. In order to more clearly and intuitively describe the implementation mode of the fault detection circuit, the structure of the garden tool to which the fault detection circuit belongs is simplified in the subsequent embodiments, and will not be described in detail.

[0060] Based on the above content, the application also provides another fault detection circuit. As shown in Figure 3 The fault detection circuit 40 provided in the application includes a pre-charge circuit 41 and a detection circuit 42.

[0061] As shown in Figure 3 The pre-charge circuit 41 is connected in parallel with the power supply switch K0. When the power supply switch K0 is opened, the pre-charge circuit 41 closes the power supply loop formed by the direct current power supply 10 and the motor driving circuit 21 in series, and the pre-charge circuit 41 is also used to limit the current of the power supply loop. It can be understood that if the motor driving circuit 21 is faulty, a large fault current may be generated when the power supply loop is turned on, thereby affecting the safe operation of the direct current power supply 10 and even the garden tool. Through the current limiting effect of the pre-charge circuit 41, the current of the power supply loop can be effectively prevented from being too large, thereby ensuring the safety of the direct current power supply 10.

[0062] The detection circuit 42 is connected with the motor driving circuit 21, and in the case that the pre-charging circuit 41 is closed to supply the power loop and the direct current power supply 10 supplies power to the motor driving circuit 21 through the pre-charging circuit 41, the detection circuit 42 detects the electrical parameters of the motor driving circuit 21 and outputs a detection signal, and correspondingly, the detection circuit 42 outputs different detection signals in the fault state and the normal state of the motor driving circuit 21.

[0063] In summary, the fault detection circuit provided in the application can limit the current of the power supply loop through the pre-charging circuit based on the foregoing embodiments, so as to avoid the generation of excessive fault current in the power supply loop in the case of failure of the motor driving circuit, and ensure the safe operation of the direct current power supply and the motor driving circuit.

[0064] Further, the application provides another fault detection circuit, as shown in Figure 4 The pre-charging circuit 41 includes a pre-charging switch K1 and a pre-charging resistor R1, and the detection circuit 42 includes a first voltage detection circuit 421, wherein the first voltage detection circuit 421 includes a first voltage dividing resistor R2 and a second voltage dividing resistor R3.

[0065] As shown in Figure 4 One end of the pre-charging switch K1 is connected with one end of the power supply switch K0, the other end of the pre-charging switch K1 is connected with one end of the pre-charging resistor R1, and the other end of the pre-charging resistor R1 is connected with the other end of the power supply switch K0, that is, the pre-charging switch K1 and the pre-charging resistor R1 are connected in series to form a series branch, and the series branch is connected with the power supply switch K0 in parallel.

[0066] One end of the first voltage dividing resistor R2 is connected with the positive terminal of the motor driving circuit 21, the other end of the first voltage dividing resistor R2 is connected with one end of the second voltage dividing resistor R3, the other end of the second voltage dividing resistor R3 is connected with the negative terminal of the motor driving circuit 21, and further, the connection point A of the first voltage dividing resistor R2 and the second voltage dividing resistor R3 serves as the output end of the first voltage detection circuit 421. Based on the above connection relationship, the first voltage detection circuit 421 is used for detecting the working voltage of the motor driving circuit 21 and outputting a first voltage detection signal.

[0067] In an alternative embodiment, the fault detection circuit can further comprise a main controller, or the fault detection circuit can share the main controller with the motor driving circuit. The main controller is connected to the control terminal of the power supply switch K0, the control terminal of the pre-charge switch K1, and the output terminal of the first voltage detection circuit 421. Based on this, the main controller can control the power supply switch K0 to be open, and at the same time, control the pre-charge switch K1 to be closed. The DC power supply 10 supplies power to the motor driving circuit 21 through the pre-charge circuit 41, and a corresponding DC voltage is generated between the positive terminal and the negative terminal of the motor driving circuit 21. The first voltage detection circuit 421 is connected in parallel with the motor driving circuit 21, detects the working voltage of the motor driving circuit 21, and outputs a corresponding detection voltage, i.e., a first voltage detection signal, after being divided by the first voltage dividing resistor R2 and the second voltage dividing resistor R3. In the normal state of the motor driving circuit 21, the first voltage detection circuit 421 outputs a first voltage, and correspondingly, in the fault state of the motor driving circuit 21, the first voltage detection circuit 421 outputs a second voltage, so that the application outputs different detection signals in the fault state and the normal state of the motor driving circuit 21, respectively.

[0068] As an alternative embodiment, the main controller can be pre-configured with a first voltage threshold. If the voltage value provided by the first voltage detection circuit 421 is greater than the first voltage threshold, it indicates that the motor driving circuit 21 is faulty, and correspondingly, if the voltage value provided by the first voltage detection circuit 421 is less than or equal to the first voltage threshold, it indicates that the motor driving circuit 21 is normal. The specific selection of the first voltage threshold can be determined based on the working voltage in the normal operating state of the motor driving circuit 21 or the output voltage of the DC power supply 10, and the application does not limit the specific value of the first voltage threshold.

[0069] Further, the main controller receives the first voltage detection signal provided by the first voltage detection circuit 421, and determines the operating state of the motor driving circuit 21 according to the first voltage detection signal. If the motor driving circuit 21 is in a normal state, the main controller can further control the power supply switch K0 to be closed, and then control the pre-charge switch K1 to be open. At this time, the power supply switch K0 supplies power to the motor driving circuit 21. If the motor driving circuit 21 is in a fault state, the main controller does not control the power supply switch K0 to be closed, and at the same time, controls the pre-charge switch K1 to be open, to prevent the fault from further expanding to the DC power supply 10.

[0070] It can be understood that in actual application, the pre-charge circuit 41 itself can also be faulty, for example, the pre-charge switch K1 is mistakenly turned on, and the main controller can also detect the running state of the pre-charge circuit 41. Specifically, a second voltage threshold is configured in the main controller, the main controller controls the power supply switch K0 and the pre-charge switch K1 to be turned off, and the main controller collects the voltage value of the first voltage detection circuit 421. If the pre-charge switch K1 is normal, at this time it will be in the off state, then the obtained voltage value should be less than or equal to the second voltage threshold, and if the pre-charge switch K1 is abnormal and is in the mistaken on state, the motor driving circuit 21 is in communication with the direct current power supply 10, and the voltage value provided by the first voltage detection circuit 421 will be greater than the second voltage threshold. Based on this, it can be determined that the pre-charge switch K1 is mistakenly turned on. As for the specific value of the second voltage threshold, it can be set in combination with the induced voltage that can exist in the motor driving circuit 21 in the off state of the power supply switch K0 and the pre-charge switch K1, and the specific value of the second voltage threshold is not limited in the present application.

[0071] In actual application, the pre-charge switch can adopt any one of an insulated gate bipolar transistor, a turn-off thyristor, a power transistor, a silicon controlled switch tube and a silicon carbide metal oxide switch tube, of course, other types of controllable switch tubes can also be selected, and as long as the core idea of the present application is not exceeded, it also belongs to the protection range of the present application.

[0072] The present application also provides another fault detection circuit, which is based on the embodiment shown in Figure 4 The fault detection circuit provided in the present embodiment further comprises a second voltage detection circuit. Referring to Figure 5 In the fault detection circuit provided in the present embodiment, the second voltage detection circuit 422 is connected with the direct current power supply 10, used for detecting the power supply voltage of the direct current power supply 10 and outputting a second voltage detection signal.

[0073] Specifically, the second voltage detection circuit comprises a third voltage dividing resistor R4 and a fourth voltage dividing resistor R5. Referring to Figure 5 One end of the third voltage dividing resistor R4 is connected with the positive terminal of the direct current power supply 10, the other end of the third voltage dividing resistor R4 is connected with one end of the fourth voltage dividing resistor R5, the other end of the fourth voltage dividing resistor R5 is connected with the negative terminal of the direct current power supply 10, and the connection point B of the third voltage dividing resistor R4 and the fourth voltage dividing resistor R5 is used as the output end of the second voltage detection circuit 422, used for outputting the second voltage detection signal.

[0074] Referring to Figure 5As shown, the first voltage detection circuit 421 is connected in parallel with the motor drive circuit 21, and the second voltage detection circuit 422 is connected in parallel with the DC power supply 10. Ignoring the voltage drop of the power supply switch K0, if the motor drive circuit 21 is operating normally, the first voltage detection signal provided by the first voltage detection circuit 421 should be basically consistent with the second voltage detection signal provided by the second voltage detection circuit 422. However, in the case of a fault in the motor drive circuit 21, there will be a large difference between the first voltage detection signal and the second voltage detection signal. Therefore, the operating status of the motor drive circuit 21 can be determined based on the signal difference between the first voltage detection signal and the second voltage detection signal.

[0075] Specifically, in Figure 5 In the illustrated embodiment, when the power supply switch K0 is open and the pre-charge switch K1 is closed, the voltage difference between the voltage provided by the first voltage detection circuit 421 and the voltage provided by the second voltage detection circuit can be calculated. If the obtained voltage difference is greater than a preset third voltage threshold, it indicates that there is a significant difference between the operating voltage of the motor drive circuit 21 and the output voltage of the DC power supply 10. Based on this, it can be determined that the motor drive circuit 21 is in a fault state, and the pre-charge switch K1 can be further opened. Conversely, if the obtained voltage difference is less than or equal to the third voltage threshold, it indicates that the difference between the operating voltage of the motor drive circuit 21 and the output voltage of the DC power supply 10 is small, and the motor drive circuit 21 is in a normal state. The power supply switch K0 can be further closed, and then the pre-charge switch K1 is closed, and the DC power supply 10 normally supplies power to the motor drive circuit 21. As for the specific value of the third voltage threshold, it can be determined by combining various factors such as the voltage division ratio of the first voltage detection circuit 421 and the second voltage detection circuit 422, the output voltage of the DC power supply 10, and the detection accuracy requirements of the fault detection circuit. This application does not limit the specific value of the third voltage threshold.

[0076] In an optional embodiment, the fault detection circuit further includes the aforementioned main controller, which is connected to the output terminals of the first voltage detection circuit 421 and the second voltage detection circuit respectively, receives the aforementioned first voltage detection signal and second voltage detection signal, and controls the conduction state of the power supply switch K0 and the precharge switch K1. Based on this, the aforementioned process of calculating the voltage difference and comparing the voltage difference with the third voltage threshold can both be implemented by the main controller.

[0077] Furthermore, this application provides another fault detection circuit, see [link to relevant documentation]. Figure 6 As shown, the fault detection circuit provided in this embodiment includes a current detection circuit 423.

[0078] like Figure 6As shown, the current detection circuit 423 is connected in series between the DC power supply 10 and the motor driving circuit 21, and the working current of the motor driving circuit 21 can be detected through the current detection circuit 423 and a current detection signal can be output. The current detection circuit 423 can output different current detection signals in the fault state and the normal state of the motor driving circuit 21. Specifically, in the case that the motor driving circuit 21 is in normal operation, the normal working current flows in the power supply circuit, the current detection circuit 423 detects the working current and outputs a corresponding first current detection signal. Correspondingly, in the case that the motor driving circuit 21 is in a fault state, the fault current flows in the power supply circuit, the current detection circuit 423 detects the fault current and outputs a corresponding second current detection signal. Based on this, the running state of the motor driving circuit 21 can be determined by identifying the current detection signal provided by the current detection circuit 423, and in the case that the motor driving circuit 21 is determined to be in a fault state, the power supply switch K0 and the pre-charge switch K1 are controlled to be turned off, so as to prevent the fault from further expanding.

[0079] In an alternative embodiment, referring to the foregoing embodiments, the fault detection circuit provided in the embodiment is provided with a main controller, the main controller is pre-configured with a first current threshold, the main controller is connected with the output end C of the current detection circuit 423 and receives the current detection signal fed back by the current detection circuit 423, the current detection signal is a specific sampling current value, if the obtained sampling current value is greater than or equal to the preset first current threshold, it is determined that the motor driving circuit 21 is in a fault state, and correspondingly, if the obtained current sampling value is less than the first current value, it is determined that the motor driving circuit 21 is in a normal state. As for the specific value of the first current threshold, it can be determined in combination with the rated working current of the motor driving circuit 21 and the accuracy requirement of fault detection and other related factors, and the specific value of the first current threshold is not limited in the present application.

[0080] Further, as mentioned before, the pre-charge circuit 41 itself can also be faulty, for example, the pre-charge switch K1 is mis-conducting, the main controller can also cooperate with the current detection circuit 423 to detect the running state of the pre-charge circuit 41. Specifically, a second current threshold is configured in the main controller, the main controller controls the power supply switch K0 and the pre-charge switch K1 to be disconnected, and the main controller collects the current value of the current detection circuit 423. If the pre-charge switch K1 is normal, it will be in the disconnected state at this time, and then the obtained current value should be less than or equal to the second current threshold. If the pre-charge switch K1 is abnormal and mis-conducting, the motor driving circuit 21 is in communication with the direct current power supply 10, and the current value provided by the current detection circuit 423 will be greater than the second current threshold. Based on this, it can be determined that the pre-charge switch K1 is mis-conducting. As for the specific value of the second current threshold, it can be set in combination with the induced current that can exist in the motor driving circuit 21 in the disconnected state of the power supply switch K0 and the pre-charge switch K1. The specific value of the second current threshold is not limited in the present application.

[0081] It should be noted that in the foregoing various embodiments, various optional embodiments of fault detection circuits are provided. These embodiments of the detection circuit can be used in combination with each other, so as to obtain more optional fault detection circuits.

[0082] For example, referring to the embodiment shown in Figure 7 , the fault detection circuit provided in this embodiment includes a second voltage detection circuit 422 and a current detection circuit 423. In addition to the method provided in the foregoing embodiments for detecting the running state of the motor driving circuit 21, the product of the current value fed back by the current detection circuit 423 and the equivalent impedance value of the motor driving circuit 21 can be calculated under the condition that the equivalent impedance value of the motor driving circuit 21 is basically stable, and then the detection voltage of the motor driving circuit 21 is obtained, that is, the function of the first voltage detection circuit 421 in the foregoing embodiment is realized. Further, reference can be made to the related content of the embodiment shown in Figure 5 , the calculated detection voltage is compared with the power supply voltage fed back by the second voltage detection circuit 422, so as to determine the running state of the motor driving circuit 21, and the specific process will not be described here in detail.

[0083] For another example, referring to the embodiment shown in Figure 8 , the fault detection circuit provided in this embodiment includes a first voltage detection circuit 421, a second voltage detection circuit 422 and a current detection circuit 423, and double detection of the working voltage and the working current of the motor driving circuit 21 is realized.

[0084] Specifically, the power supply switch K0 is controlled to be open, the pre-charge switch K1 is controlled to be closed, the voltage values fed back by the first voltage detection circuit 421 and the second voltage detection circuit 422 and the current value fed back by the current detection circuit 423 are obtained, and then the voltage difference between the voltage value of the motor driving circuit 21 (fed back by the first voltage detection circuit 421) and the voltage value of the direct current power supply 10 (fed back by the second voltage detection circuit) is calculated. If the voltage difference and the current value fed back by the current detection circuit 423 both meet the requirements, it is indicated that the motor driving circuit is normal, and the power supply switch K0 can be further controlled to be closed and the pre-charge switch K1 can be further controlled to be open. Conversely, if either the voltage difference or the current value does not meet the requirements, it is determined that the motor driving circuit 21 is faulty, and the pre-charge switch K1 and the power supply switch K0 are further closed.

[0085] Of course, other combinations can also be made to obtain different fault detection circuits. For example, the detection circuit can simultaneously include the current detection circuit and the first voltage detection circuit 421, and the like, which will not be listed one by one here, and as long as the core idea of the present application is not exceeded, it also belongs to the scope of protection of the present application.

[0086] Further, the present application also provides a garden tool, comprising:

[0087] a direct current power supply;

[0088] an actuator for being driven to perform a garden work;

[0089] a driving device electrically connected with the direct current power supply to form a power supply loop and working when the power supply loop is closed to drive the actuator, the driving device comprising a motor and a motor driving circuit;

[0090] a power supply switch connected in series in the power supply loop to open or close the power supply loop;

[0091] The garden tool further comprises the fault detection circuit provided in any of the preceding embodiments, the fault detection circuit being connected in series in the power supply loop and closing the power supply loop when the power supply switch is open to output a detection signal, wherein the fault detection circuit outputs different detection signals in the fault state and the normal state of the motor driving circuit, respectively.

[0092] Those skilled in the art can understand that the content disclosed in the present application can have various modifications and improvements. For example, the various devices or components described above can be implemented by hardware, or by software, firmware, or a combination of some or all of the three.

[0093] In addition, although the present disclosure makes various references to certain units in the system according to the embodiments of the present disclosure, however, any number of different units can be used and run on the client and / or server. The units are only illustrative, and different aspects of the system and method can use different units.

[0094] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0095] The foregoing is a summary of the present disclosure, and is not to be considered as limiting its scope. While several exemplary embodiments of the present disclosure have been described, it will be apparent to those of ordinary skill in the art that many modifications are possible without departing from the novel teachings and advantages of the present disclosure. The presently disclosed embodiments are therefore intended to be illustrative rather than limiting, with the true scope of the present disclosure being indicated by the following claims and their equivalents. Accordingly, all modifications are intended to be included within the scope of the present disclosure as defined in the following claims and their equivalents. It is furthermore to be understood that the use of relational terms such as first, second, top and bottom or up and down or front and back or back and forth will be understood to be used herein for descriptive purposes only and converted to a position as the case can be (for example, a top surface could become a bottom surface when the device is inverted, a front surface could become a back surface when the device is rotated to face the opposite direction, etc.).

Claims

1. A fault detection circuit of a garden tool, the garden tool comprising: a direct current power supply; an actuator configured to be driven to perform a garden work; a driving device electrically connected with the direct current power supply to form a power supply loop, and working when the power supply loop is closed to drive the actuator, the driving device comprising a motor and a motor driving circuit; a power supply switch connected in series with the power supply loop to open or close the power supply loop; characterized in that: the fault detection circuit is connected in series with the power supply loop, and closes the power supply loop when the power supply switch is opened to output a detection signal, wherein the fault detection circuit outputs different detection signals in a fault state and a normal state of the motor driving circuit respectively.

2. The fault detection circuit of claim 1, wherein, the fault detection circuit comprises: a pre-charge circuit connected in parallel with the power supply switch, the pre-charge circuit closing the power supply loop when the power supply switch is opened and limiting the current of the power supply loop; a detection circuit connected with the motor driving circuit to detect an electrical parameter of the motor driving circuit and output the detection signal when the pre-charge circuit closes the power supply loop.

3. The fault detection circuit of claim 2, wherein, the pre-charge circuit comprises: a pre-charge switch, one end of the pre-charge switch being connected with one end of the power supply switch; a pre-charge resistor, one end of the pre-charge resistor being connected with the other end of the pre-charge switch, and the other end of the pre-charge resistor being connected with the other end of the power supply switch.

4. The fault detection circuit of claim 2, wherein, the detection circuit comprises: a first voltage detection circuit connected with the motor driving circuit to detect a working voltage of the motor driving circuit and output a first voltage detection signal.

5. The fault detection circuit of claim 4, wherein, the first voltage detection circuit comprises: a first voltage dividing resistor, one end of the first voltage dividing resistor being connected with a positive terminal of the motor driving circuit; a second voltage dividing resistor, one end of the second voltage dividing resistor being connected with the other end of the first voltage dividing resistor, and the other end of the second voltage dividing resistor being connected with a negative terminal of the motor driving circuit.

6. A fault detection circuit according to claim 4 or 5, characterised in that, the detection circuit further comprises: a second voltage detection circuit connected with the direct current power supply to detect a power supply voltage of the direct current power supply and output a second voltage detection signal.

7. The fault detection circuit of claim 6, wherein, the second voltage detection circuit comprises: a third voltage dividing resistor, one end of the third voltage dividing resistor being connected with a positive terminal of the direct current power supply; a fourth voltage dividing resistor, one end of the fourth voltage dividing resistor being connected with the other end of the third voltage dividing resistor, and the other end of the fourth voltage dividing resistor being connected with a negative terminal of the direct current power supply.

8. The fault detection circuit of claim 2, wherein, the detection circuit comprises: a current detection circuit connected in series between the direct current power supply and the motor driving circuit to detect a working current of the motor driving circuit and output a current detection signal.

9. The fault detection circuit of claim 3, wherein, the pre-charge switch comprises any one of an insulated gate bipolar transistor, a gate-commutated thyristor, a power transistor, a thyristor, and a silicon carbide metal-oxide-semiconductor switch. 10.A garden tool comprising: a direct current power supply; an actuator configured to be driven to perform a garden work; a driving device electrically connected with the direct current power supply to form a power supply loop, and working when the power supply loop is closed to drive the actuator, the driving device comprising a motor and a motor driving circuit; A power supply switch is connected in series with the power supply circuit to open or close the power supply circuit. The garden tool further comprises: A fault detection circuit is connected in series with the power supply circuit and closes the power supply circuit to output a detection signal when the power supply switch is opened. The fault detection circuit outputs different detection signals in a fault state and a normal state of the motor driving circuit, respectively.

Images