Electric working machine

Abstract

To provide an electric working machine capable of appropriately coping with a case where a failure of a switch cannot be detected.SOLUTION: The electric working machine includes a motor, a motor drive circuit, a detector, a first mounting part, a first discharging path, a first switching part, and a controller. The controller is configured or programmed to acquire the induced voltage value from the voltage-related value detected by the detector before power of the first battery is supplied to the motor based on the first battery being attached to the first attachment portion. The controller is configured to execute a diagnosis process of diagnosing a failure of the first switching unit based on the induced voltage value being smaller than a threshold value. The control unit executes abnormality processing different from the diagnosis processing based on the induced voltage value being larger than the threshold value.SELECTED DRAWING: Figure 10B

Description

[Technical Field]

[0001] The present disclosure relates to an electric work machine equipped with a motor. [Background technology]

[0002] The hand-pushed electric cart described in Patent Document 1 includes a battery attachment section to which a battery is attached, a motor, a motor drive circuit, a switch arranged on a discharge path between the battery attachment section and the motor drive circuit, and a microcomputer (hereinafter referred to as "MCU") that controls the switch. In the hand-pushed electric cart, power is supplied or cut off from the battery to the motor drive circuit by turning the switch on or off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6969921 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described hand-pushed electric cart, the microcomputer may execute a diagnostic process to determine whether or not a switch has failed, assuming that the battery voltage is greater than the motor voltage, before driving the motor. Here, the motor may be rotated by an external force. In particular, when the hand-pushed electric cart goes downhill, the motor may be rotated by an external force. When the motor rotates by an external force, an induced voltage is generated in the motor. If the induced voltage generated in the motor becomes greater than the battery voltage, the microcomputer may not be able to detect a switch failure even after executing the diagnostic process. In other words, even if the switch is faulty, the switch failure may be overlooked.

[0005] One aspect of the present disclosure provides an electric operating machine that can take appropriate action when a switch failure cannot be detected. [Means for solving the problem]

[0006] An electric work machine according to one aspect of the present disclosure includes a motor, a motor drive circuit, a detector, a first attachment portion, a first discharge path, a first switch, and a controller. The motor drive circuit controls a current flowing through the motor. The detector detects a voltage-related value related to the voltage of the motor. A first battery is attached to the first attachment portion, and the first discharge path connects the first attachment portion to the motor drive circuit. The first switch is disposed on the first discharge path and is in a conductive state that connects the first discharge path or in a cut-off state that cuts off the first discharge path. The controller controls the first switch and the motor drive circuit to supply power from the first battery to the motor. Based on the attachment of the first battery to the first attachment portion, the controller acquires an induced voltage value corresponding to the magnitude of an induced voltage generated in the motor from the voltage-related value detected by the detector before supplying power from the first battery to the motor. Based on the induced voltage value being equal to or less than a threshold, the controller executes a diagnostic process to diagnose a fault in the first switch. The control unit executes an abnormality process different from the diagnosis process based on the induced voltage value being greater than the threshold value.

[0007] According to one aspect of the present disclosure, an electric operating machine executes an abnormality process different from a diagnostic process when the induced voltage value is greater than a threshold value. Therefore, when there is a possibility that a failure of the first switching unit cannot be detected, the electric operating machine can respond appropriately without executing a diagnostic process. [Brief explanation of the drawings]

[0008] [Figure 1] Fig. 1A shows an example of an electric working machine according to first and second embodiments, and Fig. 1B shows another example of an electric working machine according to first and second embodiments. [Figure 2] FIG. 2 is a plan view showing a battery box of the electric operating machine according to the first and second embodiments. [Figure 3] 1 is a perspective view showing the appearance of an operating device for an electric work machine according to first and second embodiments. [Figure 4]FIG. 2 is a diagram showing the electrical configuration of the electric operating machine according to the first and second embodiments. [Figure 5] FIG. 2 is a diagram showing the configuration of a failure detection circuit of the electric operating machine according to the first and second embodiments. [Figure 6] FIG. 3 is a diagram illustrating the operation of the failure detection circuit of the electric operating machine according to the first and second embodiments. [Figure 7] FIG. 3 is a diagram illustrating the operation of the failure detection circuit of the electric operating machine according to the first and second embodiments. [Figure 8] 4 is a flowchart showing a main process executed by a microcomputer of the electric operating machine according to the first and second embodiments. [Figure 9] 4 is a flowchart showing a failure detection process executed by a microcomputer of the electric operating machine according to the first and second embodiments. [Figure 10A] 5 is a flowchart showing a part of a possibility determination process executed by a microcomputer of the electric operating machine according to the first and second embodiments. [Figure 10B] 10 is a flowchart showing the remainder of the possibility determination process executed by the microcomputer of the electric operating machine according to the first and second embodiments. [Figure 11] 10 is a flowchart showing another example of a part of the possibility determination process executed by the microcomputer of the electric operating machine according to the first and second embodiments. [Figure 12] 10 is a flowchart showing another example of a part of the possibility determination process executed by the microcomputer of the electric operating machine according to the first and second embodiments. [Figure 13] 4 is a flowchart showing main power supply processing executed by a microcomputer of the electric operating machine according to the first and second embodiments. [Figure 14] 4 is a flowchart showing a notification process executed by a microcomputer of the electric operating machine according to the first and second embodiments. [Figure 15] 3 is a flowchart showing a motor control process executed by a microcomputer of the electric operating machine according to the first and second embodiments. [Figure 16] 10 is a flowchart showing a switch control process executed by a microcomputer of an electric operating machine according to a second embodiment. [Figure 17]10 is a diagram showing changes over time in the motor voltage value, battery voltage value, actual rotation speed, duty ratio, and switch signal of an electric operating machine according to a second embodiment. FIG. [Figure 18] FIG. 10 is a diagram showing time changes of an electric operating machine according to a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Summary of the embodiment] (1) In one embodiment, an electric operating machine having at least one of the following features may be provided. Feature 1: Motor. Feature 2: A motor drive circuit configured to control the current flowing through the motor. Feature 3: A detection unit configured to detect a voltage-related value related to the voltage of the motor. Feature 4: A first mounting portion configured to mount a first battery. · Feature 5: A first discharge path connecting the first mounting portion to the motor drive circuit. Feature 6: A first switching unit disposed on the first discharge path, the first switching unit being in a conducting state for conducting the first discharge path or in a blocking state for blocking the first discharge path. Feature 7: A control unit that controls the first switching unit and the motor drive circuit to supply power from the first battery to the motor. Feature 8: Based on the fact that the first battery is attached to the first attachment portion, the control unit obtains an induced voltage value corresponding to the magnitude of the induced voltage generated in the motor from the voltage-related value detected by the detection unit before supplying power from the first battery to the motor. Feature 9: The control unit executes a diagnostic process for diagnosing a failure in the first switching unit based on the induced voltage value being equal to or less than the threshold value. Feature 10: The control unit executes an abnormality process different from the diagnosis process based on the induced voltage value being greater than the threshold value.

[0010] An electric operating machine having at least Features 1 to 10 executes abnormality processing different from diagnostic processing when the induced voltage value is greater than the threshold value. Therefore, when there is a possibility that a failure in the first switching unit cannot be detected, the electric operating machine can respond appropriately without executing diagnostic processing.

[0011] Some embodiments may include at least one of the following features in addition to or instead of at least one of Features 1 to 10 above. Feature 11: The voltage-related value is the motor rotation speed. Feature 12: The threshold value is a first voltage value corresponding to the magnitude of the output of the first battery.

[0012] The control unit of an electric operating machine having at least Features 1 to 12 can calculate an induced voltage value from the rotation speed. The control unit can determine whether a failure in the first switching unit can be detected by comparing the induced voltage value with the first voltage value.

[0013] Some embodiments may include the following features in addition to or instead of at least one of Features 1 to 12 above. Feature 13: The abnormality processing includes applying a short circuit brake to the motor via a motor drive circuit.

[0014] When there is a possibility that a failure of the first switching unit cannot be detected, i.e., when the motor is generating power, the control unit of an electric operating machine having at least Features 1 to 10 and 13 can stop power generation of the motor by applying a short circuit brake to the motor. This reduces the induced voltage value, allowing the control unit to detect a failure of the first switching unit.

[0015] An embodiment may include at least one of the following features in addition to or instead of at least one of Features 1 to 13 above. ·Feature 14: Notification department. Feature 15: The abnormality processing includes notifying, via the notification unit, that an abnormality has occurred in the electric operating machine.

[0016] The control unit of an electric operating machine having at least Features 1 to 10, 14, and 15 causes the notification unit to notify the user that an abnormality has occurred in the electric operating machine when there is a possibility that a failure in the first switching unit cannot be detected, thereby enabling the user to recognize that an abnormality has occurred in the electric operating machine.

[0017] An embodiment may include at least one of the following features in addition to or instead of at least one of Features 1 to 15 above. Feature 16: A faulty battery detection circuit configured to receive an operating voltage and detect a fault in the first switching unit. Feature 17: The operating voltage is a voltage boosted from the voltage of the first battery. Feature 18: The threshold value is a voltage value corresponding to the magnitude of the operating voltage.

[0018] A control unit of an electric operating machine having at least features 1 to 10 and 16 to 18 can accurately determine whether a failure in the first switching unit can be detected by comparing the induced voltage value with the operating voltage value of the failure detection circuit.

[0019] An embodiment may include at least one of the following features in addition to or instead of at least one of Features 1 to 18 above. Feature 19: A second mounting portion configured to mount a second battery. · Feature 20: A second discharge path connecting the second mounting portion to the motor drive circuit. Feature 21: A second switching unit is disposed on the second discharge path and is configured to be in a conductive state for conducting the second discharge path or in a cut-off state for cutting off the second discharge path. Feature 22: The control unit controls the first switching unit, the second switching unit, and the motor drive circuit to supply power from the first battery and / or the second battery to the motor. Feature 23: The control unit, based on the fact that the first battery is attached to the first attachment portion and the second battery is attached to the second attachment portion, acquires an induced voltage value before supplying power from the first battery and the second battery to the motor. Feature 24: The control unit compares a first voltage value corresponding to the magnitude of the output of the first battery with a second voltage value corresponding to the magnitude of the output of the second battery. Feature 25: The control unit sets the threshold value to the larger of the first voltage value and the second voltage value.

[0020] When two batteries are attached to the electric working machine, the control unit of the electric working machine having at least the features 1 to 10 and 16 to 24 sets the higher of the voltage values ​​of the two batteries as the threshold value, thereby enabling the control unit to determine with high accuracy whether a failure in the first switching unit can be detected.

[0021] (2) In addition, the switching element located on the discharge path connecting the battery to the motor drive circuit is driven by a driver. The driver operates based on the voltage difference between the boosted battery voltage and the induced voltage of the motor. When the rotation speed of the motor increases due to an external force while the motor is rotating, the induced voltage generated in the motor increases, and the above-mentioned voltage difference decreases. When the voltage difference decreases, the driver's protection function is activated, causing the motor to stop and making it impossible to drive the motor again.

[0022] Another aspect of the present disclosure provides an electric operating machine that can prevent the motor from becoming unable to be restarted.

[0023] An embodiment may provide an electric power tool having at least one of the following features: Feature 26: Motor. Feature 27: A detection unit configured to detect a voltage-related value related to the voltage of the motor. Feature 28: A motor drive circuit configured to control a current flowing through a motor. Feature 29: A mounting portion configured to mount a battery. · Feature 30: A discharge path connecting the mounting part to the motor drive circuit. Feature 31: A switching element disposed on a discharge path and configured to be in a conductive state for conducting the discharge path or in a cut-off state for cutting off the discharge path. Feature 32: A switch drive circuit configured to drive a switching element. Feature 33: A control unit configured to control a switching element and a motor drive circuit to supply battery power to the motor. Feature 34: The control unit obtains an induced voltage value corresponding to the magnitude of the induced voltage generated in the motor from the voltage-related value detected by the detection unit. Feature 35: The control unit switches the switching element to the cut-off state based on the fact that, while the motor is being driven, the induced voltage value exceeds a sum obtained by adding a first predetermined value to a battery voltage value corresponding to the magnitude of the battery voltage.

[0024] The control unit of an electric work machine having at least Features 26 to 35 turns off the switching element when the motor starts generating power while the motor is running and the induced voltage value exceeds the added value, thereby reducing the rotation speed of the motor and preventing the protection function of the switch drive circuit from being activated.

[0025] Some embodiments may include the following features in addition to or instead of at least one of Features 26 to 35 described above. Feature 36: The control unit is configured to turn off the input signal to the switch drive circuit based on the induced voltage value exceeding the added value, thereby bringing the switching element into a cut-off state.

[0026] The control unit of the electric operating machine having at least Features 26 to 36 can prevent the protection function of the switch drive circuit from being activated by turning off the input signal to the switch drive circuit. An embodiment may include the following features in addition to or instead of at least one of Features 25 to 36 described above. Feature 37: The control unit is configured to turn off the power supply to the switch drive circuit based on the induced voltage value exceeding the added value, thereby bringing the switching element into a cut-off state.

[0027] The control unit of an electric operating machine having at least Features 26 to 35 and 37 can prevent the protection function of the switch drive circuit from being activated by turning off the power supply to the switch drive circuit.

[0028] Some embodiments may include the following features in addition to or instead of at least one of Features 26 to 37 described above. Feature 38: The control unit is configured to turn on the input signal to bring the switching element into a conducting state when the difference between the induced voltage value and the battery voltage value becomes smaller than a second predetermined value.

[0029] The control unit of an electric work machine having at least features 26 to 36 and 38 can resume the supply of power from the battery to the motor by turning on the input signal based on the induced voltage value becoming smaller than the battery voltage value.

[0030] Some embodiments may include the following features in addition to or instead of at least one of features 26 to 38 described above. Feature 39: The control unit is configured to turn on the power supply of the switch drive circuit based on the induced voltage value becoming smaller than the battery voltage value, thereby bringing the switching element into the conductive state.

[0031] The control unit of an electric work machine having at least features 26 to 35, 37, and 39 can resume the supply of power from the battery to the motor by turning on the power supply to the switch drive circuit based on the induced voltage value becoming smaller than the battery voltage value.

[0032] Examples of the above-mentioned electric work machines include various types of equipment configured to be used at work sites such as construction, manufacturing, gardening, and civil engineering, specifically, power tools for masonry, metalwork, and woodworking, power tools for gardening, power tools for improving the environment at work sites, fan vests, fan jackets, push carts, electric sweepers, power-assisted bicycles, and air pumps.

[0033] Examples of the power tools mentioned above include electric chainsaws, electric hand saws, electric blowers, electric hammers, electric hammer drills, electric drills, electric screwdrivers, electric wrenches, electric impact drivers, electric impact wrenches, electric grinders, electric circular saws, electric reciprocating saws, electric jigsaws, electric cutters, electric planers, electric nail guns (including tackers), electric hedge trimmers, electric lawn mowers, electric lawn clippers, electric brush cutters, electric cleaners, electric sprayers, electric spreaders, electric dust collectors, electric trowels, electric vibrators, electric rammers, electric compactors, electric pumps, electric pile drivers, electric concrete saws, electric screeds, and electric cut-off saws.

[0034] In some embodiments, the above features 1 to 39 may be combined in any manner. In some embodiments, any of the above features 1-39 may be omitted.

[0035] Specific Exemplary Embodiments Specific exemplary embodiments will now be described with reference to the drawings.

[0036] (1. First embodiment) <1-1.Configuration> <1-1-1. Overall structure> 1A and 1B, the configuration of an electric working machine 1 according to this embodiment will be described. In this embodiment, the electric working machine 1 is a rechargeable, hand-pushed transport vehicle.

[0037] The electric working machine 1 includes front wheels 3, rear wheels 5L, 5R, a body frame 10, a bed frame 20, a rear wheel frame 30, obstacle detection units 40L, 40R, a battery box 70, and an operating device 90. In the following, the suffix L of a reference symbol indicates that the target member is located on the left side when facing the front of the electric working machine 1. The suffix R of a reference symbol indicates that the target member is located on the right side when facing the front of the electric working machine 1.

[0038] In another embodiment, the electric work machine 1 may be configured such that at least one of the front wheels 3, rear wheels 5L, 5R, body frame 10, loading platform frame 20, rear wheel frame 30, obstacle detection units 40L, 40R, battery box 70, and operating device 90 is excluded.

[0039] The front wheels 3 are drive wheels and rotate by the power of a motor 13, which will be described later. The front wheels 3 also rotate when a user pushes the electric working machine 1 by hand. The rear wheels 5L, 5R are driven wheels. The electric working machine 1 is a tricycle equipped with three wheels.

[0040] The body frame 10 rotatably supports the front wheel 3 and the rear wheels 5L, 5R. The loading platform frame 20 fixes a loading platform on which cargo is placed onto the vehicle body frame 10. The loading platform frame 20 is configured so that various loading platforms can be fixed. The user can select a loading platform to be fixed to the loading platform frame 20 depending on the type of work being carried out. The loading platform 20A shown in FIG. 1A is an example of a loading platform. The loading platform 20B shown in FIG. 1B is another example of a loading platform. The loading platform 20A is a so-called pallet, and is formed by connecting multiple pipes. The loading platform 20B is a so-called bucket, and is formed by press-forming steel plate.

[0041] The body frame 10 and the bed frame 20 are made by bending rod-shaped metal pipes. The body frame 10 and the bed frame 20 sandwich the front wheels 3 and have bilaterally symmetrical shapes with respect to the plane of rotation of the front wheels 3.

[0042] The body frame 10 extends rearward from the front wheels 3 and then rises upward. The rear end of the body frame 10 is located at a height that allows a user to push the electric work machine 1 by hand. The left and right rear ends of the body frame 10 form handlebars 16L, 16R. Grips 15L, 15R are attached to the handlebars 16L, 16R. The user holds the grips 15L, 15R to push the electric work machine 1.

[0043] The body frame 10 is equipped with a brake device 17 that applies a braking force directly to the front wheel 3. The brake device 17 is disposed near the plane of rotation on the left side of the front wheel 3 and includes brake pads. The body frame 10 also has a brake lever 18 for operating the brake device 17. The brake lever 18 is disposed below the left handlebar 16L. When the user pulls the brake lever 18, the brake pads of the brake device 17 are pressed against the front wheel 3, applying a braking force to the front wheel 3. When the user releases the brake lever 18, the brake pads move away from the front wheel 3.

[0044] The rear wheel frame 30 is attached to the rear of the body frame 10. The rear wheel frame 30 carries the loading platform frame 20. The rear wheel frame 30 also supports the left and right rear wheels 5L, 5R so that they can rotate and slide in the left-right direction.

[0045] The obstacle detection unit 40L is installed on the left side of the body frame 10. The obstacle detection unit 40R (not shown) is installed in a position symmetrical to the obstacle detection unit 40L. The obstacle detection units 40L, 40R include sensors (e.g., ultrasonic sensors, laser radar) and detect the presence or absence of an obstacle ahead and the distance to the obstacle. The obstacle detection units 40L, 40R output the detected distance to a microcomputer (hereinafter referred to as microcomputer) 60, which will be described later.

[0046] The operating device 90 is installed on the right handle 16R. As shown in Figures 3 and 4, the operating device 90 is a substantially rectangular parallelepiped case. The operating device 90 includes a drive lever 91. The drive lever 91 is located below the grip 15R. The drive lever 91 is a trigger, and is operated by a user holding the grip 15R. When the user pulls the drive lever 91, a command to rotate the motor 13 is output to the microcomputer 60. When the user releases the drive lever 91, a command to stop the motor 13 is output to the microcomputer 60. The user also specifies the target rotation speed of the motor 13 by the distance the drive lever 91 is pulled.

[0047] The operating device 90 has, on its top surface, a main power switch 92, a forward / reverse selector switch 94, a forward / reverse display unit 95, a speed mode selector switch 96, and a speed mode display unit 97. The main power switch 92 is a tactile switch that is operated by the user. Each time the user presses the main power switch 92, the main power state changes from on to off or from off to on.

[0048] The main power switch 92 includes a light-emitting diode (hereinafter referred to as an LED). The main power switch 92 emits light in a first color when the main power state is on, and emits light in a second color when the main power state is off. For example, the first color is green and the second color is red.

[0049] The forward / reverse selector switch 94 is a tactile switch that is operated by the user to set the traveling direction of the electric work machine 1 to forward or backward. Each time the user presses the forward / reverse selector switch 94, the traveling direction (more specifically, the rotation direction of the motor 13) changes from forward to backward or backward to forward.

[0050] The forward / reverse display unit 95 includes an LED, and displays the direction of travel of the electric working machine 1 that has been set via the forward / reverse changeover switch 94 . The speed mode changeover switch 96 is a tactile switch that is operated by the user to set the speed mode of the motor 13 (i.e., the electric work machine 1) to high-speed mode or low-speed mode. Every time the user presses the speed mode changeover switch 96, the speed mode changes from high-speed mode to low-speed mode or from low-speed mode to high-speed mode. The speed mode display unit 97 includes an LED, and displays the speed mode set via the speed mode changeover switch 96 .

[0051] The battery box 70 has a substantially rectangular parallelepiped shape and is disposed between the left and right handlebars 16L, 16R. A first battery pack 5 and a second battery pack 6 are connected inside the battery box 70. The first battery pack 5 may be connected in parallel to the second battery pack 6 or in series to the second battery pack 6. As shown in FIG. 2, the battery box 70 is provided with remaining capacity display units 72A, 72B and a remaining capacity display switch 73 on its top surface. In this embodiment, the battery box 70 corresponds to an example of a first mounting portion and a second mounting portion in the overall embodiment.

[0052] The remaining capacity display unit 72A displays the remaining capacity of the first battery pack 5. The remaining capacity display unit 72B displays the remaining capacity of the second battery pack 6. The remaining capacity is the amount of power stored in the first battery packs 5, 6. Each of the remaining capacity display units 72A, 72B includes multiple LEDs, and lights up the number of LEDs corresponding to the remaining capacity.

[0053] The remaining capacity display switch 73 is operated by the user to display the remaining capacity of the first battery packs 5, 6. When the user presses the remaining capacity display switch 73, a display command is input to the microcomputer 60. The remaining capacity display units 72A, 72B receive the display command from the microcomputer 60 and display the remaining capacity.

[0054] The battery box 70 also includes a buzzer 68 therein. The buzzer 68 receives an output command from the microcomputer 60 and outputs a sound.

[0055] <1-1-2. Electrical configuration> The electrical configuration of the electric operating machine 1 will be described with reference to FIG.

[0056] The first battery pack 5 includes a first battery 5a and a battery detection circuit 5b. The first battery 5a is a chargeable and dischargeable secondary battery including multiple battery cells connected in series, such as a lithium-ion battery. The battery detection circuit 5b outputs a first battery state signal to the microcomputer 60 based on the state of the first battery 5a. The first battery state signal is a binary signal whose voltage is either high or low. A high level of the first battery state signal corresponds to the first battery 5a being in a normal state. A low level of the first battery state signal corresponds to the first battery 5a being in an abnormal state. The normal state indicates that the first battery 5a is in a dischargeable state. The abnormal state indicates that the first battery 5a is in an undischargeable state. For example, the abnormal state indicates that the first battery 5a is in an over-discharge state, an over-temperature state, an overload state, or the like. Furthermore, the battery detection circuit 5b detects the value of the battery voltage VB1 of the first battery 5a (hereinafter referred to as the first battery voltage value X1), and outputs the detected first battery voltage value X1 to the microcomputer 60. The first battery voltage value X1 corresponds to the magnitude of the output voltage of the first battery 5a.

[0057] The second battery pack 6 includes a second battery 6a and a battery detection circuit 6b. The second battery 6a is a chargeable and dischargeable secondary battery including a plurality of battery cells connected in series, such as a lithium-ion battery. The battery detection circuit 6b outputs a second battery state signal to the microcomputer 60 based on the state of the second battery 6a. The second battery state signal is a binary signal having high and low levels. A high level indicates that the second battery 6a is in a normal state, and a low level indicates that the second battery 6a is in an abnormal state. The battery detection circuit 6b also detects the value of a battery voltage VB2 of the second battery 6a (hereinafter referred to as a second battery voltage value X2) and outputs the detected second battery voltage value X2 to the microcomputer 60.

[0058] 4, the electric work machine 1 includes a parallel circuit, and the first battery 5a is connected in parallel to the second battery 6a. However, the electric work machine 1 may also include a series circuit, and the first battery 5a may be connected in series to the second battery 6a. Alternatively, the electric work machine 1 may include a series circuit, a parallel circuit, and a switching circuit that switches between the series circuit and the parallel circuit.

[0059] The electric work machine 1 includes a motor 13 and a rotation sensor 14 . The motor 13 is a three-phase brushless motor. The motor 13 receives a supply of electric power from the first battery 5a or the second battery 6a and rotates. The motor 13 can generate electricity by rotating due to an external force even when not receiving a supply of electric power. For example, when a user pushes the electric work machine 1 down a slope, the motor 13 receives an external force and rotates.

[0060] The rotation sensor 14 includes three Hall sensors and detects the rotational position of the rotor of the motor 13. The three Hall sensors are arranged at positions corresponding to the three-phase windings. The rotation sensor 14 outputs a position signal corresponding to the detected rotational position to the microcomputer 60. The microcomputer 60 detects the actual rotational speed of the motor 13 based on the position signal. In this embodiment, the rotation sensor 14 corresponds to an example of a general detection unit in the embodiment. In addition, in this embodiment, the actual rotational speed corresponds to an example of a voltage-related value related to the general motor voltage in the embodiment.

[0061] The electric work machine 1 includes a controller 31. The controller 31 is connected between the first battery packs 5, 6 and the motor 13. The controller 31 includes a first discharge path 81, a second discharge path 82, a motor drive circuit 61, and a capacitor 62. The motor drive circuit 61 is a three-phase full-bridge circuit including three switching elements arranged on the high side and three switching elements arranged on the low side. The motor drive circuit 61 supplies power to the motor 13 and controls the current flowing through the windings of the motor 13 based on a drive signal output from the microcomputer 60. The drive signal is a signal that rotates the motor 13. Furthermore, the motor drive circuit 61 cuts off the supply of power to the motor 13 based on a stop signal output from the microcomputer 60, stopping the motor 13.

[0062] The first discharge path 81 connects the positive electrode of the first battery 5a to the motor drive circuit 61. The second discharge path 82 connects the positive electrode of the second battery 6a to the motor drive circuit 61. The first discharge path 81 and the second discharge path 82 are common to one another in a portion on the motor drive circuit 61 side. The positive electrode of the capacitor 62 is connected to the common portion of the first discharge path 81 and the second discharge path 82. The negative electrode of the capacitor 62 is connected to ground.

[0063] The controller 31 includes a diode D3, a diode D4, a power supply circuit 64, and a power supply circuit 65. The anode of the diode D3 is connected to a first discharge path 81. The cathode of the diode D3 is connected to an input of the power supply circuit 64. The anode of the diode D4 is connected to a second discharge path 82. The cathode of the diode D4 is connected to an input of the power supply circuit 64. Therefore, when the first battery pack 5 is connected to the battery box 70 but the second battery pack 6 is not connected, power is supplied to the power supply circuit 64 from the first battery 5a. When the second battery pack 6 is connected to the battery box 70 but the first battery pack 5 is not connected, power is supplied to the power supply circuit 64 from the second battery 6a. When the first and second battery packs 5, 6 are connected to the battery box 70, power is supplied to the power supply circuit 64 from the first or second battery 5a, 6a, whichever has a higher battery voltage value.

[0064] The power supply circuit 64 steps down the battery voltage VB1 or VB2 to generate a DC power supply voltage VS1. The power supply voltage VS1 is a voltage for operating the microcomputer 60. The power supply circuit 65 steps up the power supply voltage VS1 to generate a power supply voltage VS2. The power supply voltage VS2 is a voltage for operating the boost circuits 41 and 51, which will be described later.

[0065] The controller 31 includes a boost circuit 41, a boost circuit 51, a diode D5, and a diode D6. The boost circuit 41 is connected to a first discharge path 81. The boost circuit 51 is connected to a second discharge path 82. The anode of the diode D5 is connected to the output of the boost circuit 41. The anode of the diode D6 is connected to the output of the boost circuit 51. The cathode of the diode D5 is connected to the cathode of the diode D6.

[0066] The boost circuit 41 is driven by the input of the power supply voltage VS2 and boosts the battery voltage VB1 to generate a DC power supply voltage VS5. The boost circuit 51 is driven by the input of the power supply voltage VS2 and boosts the battery voltage VB2 to generate a DC power supply voltage VS5. Therefore, when only one of the first batteries 5a, 6a is connected to the controller 31, the voltage of the connected battery is boosted to generate the power supply voltage VS5. When both first batteries 5a, 6a are connected to the controller 31, the voltage of the battery with the higher battery voltage value is boosted to generate the power supply voltage VS5. The power supply voltage VS5 is a voltage for operating the first switching circuit 43 and the second switching circuit 53, which will be described later. The power supply voltage VS5 is the first battery voltage value X1 or the second battery voltage value X2 plus a boosted voltage value ΔVS. For example, the boosted voltage value ΔVS is 12 V.

[0067] The controller 31 includes a microcomputer 60 and a switching element 63. In this embodiment, the switching element 63 is a PNP bipolar transistor. The emitter of the switching element 63 is connected to a power supply voltage VS1. The base of the switching element 63 is connected to a main power switch 92. The collector of the switching element 63 is connected to the microcomputer 60. When the main power switch 92 is in an on state, the switching element 63 is in an on state, and the power supply voltage VS1 is supplied to the microcomputer 60. When the main power switch 92 is in an off state, the switching element 63 is in an off state, and the power supply voltage VS1 is not supplied to the microcomputer 60.

[0068] The microcomputer 60 includes a CPU, memories including ROM and RAM, and an I / O. The microcomputer 60 controls the discharge of the first battery 5a and the second battery 6a. The microcomputer 60 also controls the first switching circuit 43 and the motor driving circuit 61 to supply power from the first battery 5a to the motor 13. The microcomputer 60 also controls the second switching circuit 53 and the motor driving circuit 61 to supply power from the second battery 6a to the motor 13.

[0069] Specifically, the microcomputer 60 controls switching between the conductive state and the cut-off state of the first switching circuit 43 and the second switching circuit 53. Furthermore, the microcomputer 60 sets a target rotation speed of the motor 13. Then, the microcomputer 60 generates a drive signal so that the actual rotation speed of the motor 13 becomes the target rotation speed, and outputs the generated drive signal to the motor drive circuit 61. Alternatively, the microcomputer 60 sets an output duty ratio of a pulse width modulation (hereinafter, PWM) signal corresponding to the target rotation speed. Then, the microcomputer 60 generates a PWM signal having the set output duty ratio as a drive signal, and outputs the generated PWM signal to the motor drive circuit 61. The PWM signal is applied to the windings of the motor 13 via the motor drive circuit 61. Note that in this embodiment, the microcomputer 60 corresponds to an example of a control unit of the embodiment.

[0070] The controller 31 includes a first switching circuit 43, a second switching circuit 53, a diode D1, a diode D2, a first fault detection circuit 44, and a second fault detection circuit 54. The first switching circuit 43 is arranged on a first discharge path 81. Specifically, the first switching circuit 43 is arranged between the capacitor 62 and the boost circuit 41. The diode D1 is arranged on the first discharge path 81. Specifically, the diode D1 is arranged between the first switching circuit 43 and the boost circuit 41. The anode of the diode D1 is connected to the boost circuit 41, and the cathode of the diode D1 is connected to the first switching circuit 43.

[0071] The second switching circuit 53 is arranged on the second discharge path 82. More specifically, the second switching circuit 53 is arranged between the capacitor 62 and the boost circuit 51. The diode D2 is arranged on the second discharge path 82. More specifically, the diode D2 is arranged between the second switching circuit 53 and the boost circuit 51. The anode of the diode D2 is connected to the boost circuit 51, and the cathode of the diode D2 is connected to the second switching circuit 53.

[0072] The diode D1 suppresses a reverse current flow in the first discharge path 81. That is, the diode D1 suppresses a current flow from the motor drive circuit 61 to the first battery 5a. The diode D2 suppresses a reverse current flow in the second discharge path 82. That is, the diode D2 suppresses a current flow from the motor drive circuit 61 to the second battery 6a.

[0073] The first switching circuit 43 includes a switching element 43a, a logical AND operation circuit (hereinafter referred to as an AND circuit) 43b, and a switch drive circuit 43c. In this embodiment, the switching element 43a is an N-channel MOSFET. The drain of the switching element 43a is connected to the cathode of the diode D1. The source of the switching element 43a is connected to the capacitor 62. The gate of the switching element 43a is connected to the switch drive circuit 43c. In another embodiment, the switching element 43a may be a P-channel MOSFET or an IGBT.

[0074] When the switching element 43a is on, the switching element 43a is in a conductive state and conducts the first discharge path 81. When the switching element 43a is off, the switching element 43a is in a cut-off state and cuts off (makes non-conductive) the first discharge path 81.

[0075] The second switching circuit 53 includes a switching element 53a, an AND circuit 53b, and a switch drive circuit 53c, and has the same configuration as the first switching circuit 43. That is, in this embodiment, the switching element 53a is an N-channel MOSFET. When the switching element 53a is on, the switching element 53a is in a conductive state and causes the second discharge path 82 to be conductive. When the switching element 53a is off, the switching element 53a is in a cut-off state and cuts off the second discharge path 82. In another embodiment, the switching element 53a may be a P-channel MOSFET or an IGBT.

[0076] The AND circuit 43b has three input terminals and one output terminal. The output terminal of the AND circuit 43b is connected to the switch drive circuit 43c. The first battery state signal, the first switch signal, and the second circuit state signal S22 are input to the three input terminals of the AND circuit 43b.

[0077] The second circuit status signals S21 and S22 are output from the second fault detection circuit 54 based on whether the diode D2 or the second switching circuit 53 is in a fault state. The second circuit status signal S21 is input to the microcomputer 60, and the second circuit status signal S22 is input to the ADN circuit 43b. The second circuit status signals S21 and S22 are binary signals whose voltages are high or low. A high level of the second circuit status signals S21 and S22 corresponds to the diode D2 and the second switching circuit 53 not being in a fault state (normal state). A low level of the second circuit status signals S21 and S22 corresponds to the diode D2 or the second switching circuit 53 being in a fault state. Specifically, the second switching circuit 53 being in a fault state corresponds to the diode D2 or the switching element 53a being short-circuited.

[0078] The first switch signal is output from the microcomputer 60. The first switch signal is a binary signal that is either high or low. When at least one of the first circuit state signal S11 and the second circuit state signal S21 is low, the microcomputer 60 sets the first switch signal to low.

[0079] The first circuit state signals S11 and S12 are output from the first fault detection circuit 44 based on whether the diode D1 or the first switching circuit 43 is in a fault state. The first circuit state signal S11 is input to the microcomputer 60, and the second circuit state signal S12 is input to the AND circuit 53b. The first circuit state signals S11 and S12 are binary signals whose voltages are either high or low. A high level of the first circuit state signals S11 and S12 corresponds to the diode D1 and the first switching circuit 43 not being in a fault state. A low level of the first circuit state signals S11 and S12 corresponds to the diode D1 or the first switching circuit 43 being in a fault state. Specifically, a fault state of the first switching circuit 43 corresponds to the diode D1 or the switching element 43a being short-circuited.

[0080] When the first circuit state signal S11, the second circuit state signal S21, and the first battery state signal are at a high level and the second battery state signal is at a low level, the microcontroller 60 sets the first switch signal to a high level and sets the second switch signal, which will be described later, to a low level.

[0081] When the first circuit state signal S11, the second circuit state signal S21, and the second battery state signal are at a high level and the first battery state signal is at a low level, the microcontroller 60 sets the first switch signal to a low level and sets the second switch signal to a high level.

[0082] When the first circuit state signal S11, the second circuit state signal S21, the first battery state signal, and the second battery state signal are at a high level and the first battery voltage value X1 is greater than the second battery voltage value X2, the microcomputer 60 sets the first switch signal to a high level and sets the second switch signal to a low level.

[0083] When the first circuit state signal S11, the second circuit state signal S21, the first battery state signal, and the second battery state signal are at a high level and the second battery voltage value X2 is greater than the first battery voltage value X1, the microcomputer 60 sets the first switch signal to a low level and sets the second switch signal to a high level.

[0084] The switch drive circuit 43c outputs a gate drive signal to the gate of the switching element 43a. The gate drive signal is a binary signal whose voltage is either high or low. When the gate drive signal is high, the switching element 43a is turned on. When the gate drive signal is low, the switching element 43a is turned off.

[0085] The AND circuit 43b outputs an input signal to the switch drive circuit 43c. The input signal becomes high level when the first battery state signal, the first switch signal, and the second circuit state signal S22 are high level. The input signal becomes low level when any of the first battery state signal, the first switch signal, and the second circuit state signal S22 is low level.

[0086] The switch drive circuit 43c outputs a high-level gate drive signal when the power is on and the input signal is high. The switch drive circuit 43c outputs a low-level input signal when the power is off or the input signal is low. The power supply of the switch drive circuit 43c is controlled by the microcomputer 60.

[0087] The second switching circuit 53 has the same configuration as the first switching circuit 43, and therefore details thereof will be omitted.

[0088] <1-1-3. Fault detection circuit> The configuration of the first fault detection circuit 44 will be described with reference to FIG. 5. The second fault detection circuit 54 has a similar configuration to the first fault detection circuit 44, and therefore details thereof will be omitted. The first fault detection circuit 44 detects faults in the diode D1 and the first switching circuit 43. The first fault detection circuit 44 includes a diode D11, resistors R1, R2, R3, and R4, inverting circuits (hereinafter referred to as NOT circuits) N1 and N2, and a switching element T1. In this embodiment, the switching element T1 is a PNP-type bipolar transistor. Each of the resistors R1, R2, R3, and R4 has a first end and a second end.

[0089] The cathode of the diode D11 is connected between the diode D1 and the switching element 43a in the first discharge path 81. The anode of the diode D11 is connected to a first end of the resistor R2. The second end of the resistor R2 is connected to a second end of the resistor R1 and the base of the switching element T1. The first end of the resistor R1 is connected to the power supply voltage VS5 and the emitter of the switching element T1. The collector of the switching element T1 is connected to a first end of the resistor R3. The second end of the resistor R3 is connected to a second end of the resistor R4, an input terminal of the NOT circuit N1, and an input terminal of the NOT circuit N2. The first end of the resistor R4 is connected to ground. The output terminal of the NOT circuit N1 is connected to the microcomputer 60. The output terminal of the NOT circuit N2 is connected to an input terminal of the AND circuit 53b.

[0090] Before supplying power from the first battery 5a to the motor 13, the microcomputer 60 detects a short circuit in the diode D1 and the first switching circuit 43 via the first fault detection circuit 44. That is, after the first battery 5a is connected to the battery box 70 and the main power switch 92 is turned on, and while the supply of power from the motor drive circuit 61 to the motor 13 is being cut off, the microcomputer 60 detects a short circuit in the diode D1 and the first switching circuit 43 via the first fault detection circuit 44.

[0091] Therefore, normally, when the motor 13 is stopped, the microcomputer 60 executes a diagnostic process to diagnose whether or not there is a fault in the diode D1 and the first switching circuit 43 via the first fault detection circuit 44. However, even when the motor 13 is not receiving power from the first battery 5a and the second battery 6a, the motor 13 may receive an external force to rotate and generate power. When the motor 13 is generating power, the microcomputer 60 may not be able to detect a short circuit in the diode D1 or the first switching circuit 43.

[0092] 6 shows the operations of the diode D1, the switching element 43a, and the switching element T1 under normal conditions (i.e., when the motor 13 is stopped), and the levels of the first circuit state signals S11 and S12. Note that the diode D1 being in the on state corresponds to the diode D1 being short-circuited, and the diode D1 being in the off state corresponds to the diode D1 not being short-circuited.

[0093] When the diode D1 and the switching element 43a are in the OFF state, i.e., when the diode D1 and the switching element 43a are not short-circuited, no base current flows, and the switching element T1 is in the OFF state. Therefore, a low-level signal is input to each of the NOT circuits N1 and N2. Therefore, the first circuit state signals S11 and S12 are at a high level.

[0094] When the diode D1 is on and the switching element 43a is off, i.e., when the diode D1 is short-circuited, the switching element T1 is on. Therefore, a high-level signal is input to each of the NOT circuits N1 and N2. Therefore, the first circuit state signals S11 and S12 are low.

[0095] When the diode D1 is off and the switching element 43a is on, i.e., when the switching element 43a is short-circuited, the switching element T1 is on. Therefore, a high-level signal is input to each of the NOT circuits N1 and N2. Therefore, the first circuit state signals S11 and S12 are low.

[0096] When the diode D1 is on and the switching element 43a is on, i.e., when the diode D1 and the switching element 43a are short-circuited, the switching element T1 is on. Therefore, a high-level signal is input to each of the NOT circuits N1 and N2. Therefore, the first circuit state signals S11 and S12 are low.

[0097] Therefore, when the diode D1 and the switching element 43a are not short-circuited, the first circuit state signals S11 and S12 are high level, and when at least one of the diode D1 and the switching element 43a is short-circuited, the first circuit state signals S11 and S12 are low level.

[0098] FIG. 7 shows the operations of the diode D1, the switching element 43a, and the switching element T1, and the levels of the first circuit state signals S11 and S12 when the motor is generating power. When the motor 13 is generating power, the voltage VS6 of the capacitor 62 is equal to the induced voltage generated in the windings of the motor 13. The voltage VS6 of the capacitor 62 is propagated to the first battery 5a via the parasitic diode of the switching element 43a. Therefore, the voltage VS7 at the cathode of the diode D11 is approximately equal to the voltage VS6. Therefore, when the induced voltage of the motor 13 becomes higher than the power supply voltage VS5, no base current flows through the switching element T1, and the switching element T1 is turned off. In other words, when the induced voltage of the motor 13 becomes higher than the power supply voltage VS5, the switching element T1 is turned off even if the diode D1 or the switching element 43a is short-circuited.

[0099] Therefore, when the motor 13 is generating power, the first circuit state signals S11 and S12 may become high even if the diode D1 or the switching element 43a is short-circuited. Therefore, the microcomputer 60 may recognize that the diode D1 or the switching element 43a is not short-circuited, even when it is. Ultimately, even if the diode D1 or the switching element 43a is actually short-circuited, the microcomputer 60 may execute the same control as if the diode D1 and the switching element 43a were not short-circuited, potentially causing a malfunction in the electric work machine 1. Therefore, the microcomputer 60 executes a feasibility determination process before executing the diagnostic process and diagnosing the presence or absence of a fault in the diode D1 and the first switching circuit 43 via the first fault detection circuit 44. Similarly, the microcomputer 60 executes a feasibility determination process before executing the diagnostic process and diagnosing the presence or absence of a fault in the diode D2 and the second switching circuit 53 via the second fault detection circuit 54. Details of the feasibility determination process will be described later.

[0100] <1-2. Processing> <1-2-1. Main processing> Next, the main processing executed by the microcomputer 60 will be described with reference to the flowchart in Fig. 8. The microcomputer 60 starts this processing in response to the main power switch 92 being turned on. The microcomputer 60 repeatedly executes this processing at a predetermined interval.

[0101] In S10, the microcomputer 60 executes a fault detection process. That is, the microcomputer 60 executes a possibility determination process before executing a diagnostic process using the first fault detection circuit 44 and the second fault detection circuit 54. Furthermore, if the microcomputer 60 determines that the diagnostic process is possible, it executes the diagnostic process using the first fault detection circuit 44 and the second fault detection circuit 54. The diagnostic process will be described in detail later.

[0102] Next, in S20, the microcomputer 60 executes main power supply processing. That is, the microcomputer 60 determines whether the main power supply is in an on state or an off state. The main power supply processing will be described in detail later. Next, in S30, the microcomputer 60 executes a notification process. That is, the microcomputer 60 notifies that a fault cannot be detected. The microcomputer 60 also notifies that a fault has been detected in either the diodes D1, D2 or the first or second switching circuit 43, 53. The notification process will be described in detail later.

[0103] Next, in S40, the microcomputer 60 executes a motor control process. That is, the microcomputer 60 generates a drive signal based on the state of the first battery 5a, the state of the second battery 6a, the state of the controller 31, the distance the drive lever 91 has been pulled, etc. Then, the microcomputer 60 outputs the generated drive signal to the motor drive circuit 61. The motor control process will be described in detail later.

[0104] <1-2-2. Fault detection processing> Next, the fault detection process executed by the microcomputer 60 in S10 will be described with reference to the flowchart of FIG.

[0105] In S100, the microcomputer 60 executes a feasibility determination process. If the microcomputer 60 determines that the diagnostic process using the first fault detection circuit 44 and the second fault detection circuit 54 is not possible, the microcomputer 60 sets a rotation error flag. On the other hand, if the microcomputer 60 determines that the diagnostic process using the first fault detection circuit 44 and the second fault detection circuit 54 is possible, the microcomputer 60 clears the rotation error flag. The feasibility determination process will be described in detail later.

[0106] In S110, if the rotation error flag is cleared, the microcomputer 60 executes a diagnostic process using the first fault detection circuit 44 and the second fault detection circuit 54. Specifically, if at least one of the first circuit status signal S11 and the second circuit status signal S21 is at a low level, the microcomputer 60 sets the fault error flag. If both the first circuit status signal S11 and the second circuit status signal S21 are at a high level, the microcomputer 60 clears the fault error flag.

[0107] <1-2-3. Possibility determination process> Next, the possibility determination process executed by the microcomputer 60 in S100 will be described with reference to the flowcharts of FIGS. 10A and 10B.

[0108] In S200, the microcomputer 60 determines whether the rotation error flag is set. If the microcomputer 60 determines that the rotation error flag is set (S200: YES), the microcomputer 60 proceeds to processing of S210. If the microcomputer 60 determines that the rotation error flag is cleared (S200: NO), the microcomputer 60 proceeds to processing of S220.

[0109] In S210, the microcomputer 60 determines whether to cancel the rotation error. Specifically, the microcomputer 60 determines to cancel the rotation error if the brake lever 18 is pulled and the drive lever 91 is released, and determines not to cancel the rotation error in other cases. That is, the microcomputer 60 cancels the rotation error if the brake is on and the trigger is off. Then, the microcomputer 60 ends this process.

[0110] In S220, the microcomputer 60 determines whether the first battery pack 5 or the second battery pack 6 has been attached to the battery box 70. That is, the microcomputer 60 determines whether the first battery 5a or the second battery 6a has changed from a state where it is not connected to the controller 31 to a state where it is connected. The microcomputer 60 determines whether the first battery pack 5 or the second battery pack 6 has been attached to the battery box 70 based on the first battery voltage value X1, the second battery voltage value X2, the presence or absence of communication with the first battery pack 5, the presence or absence of communication with the second battery pack 6, etc. If the microcomputer 60 determines that the first battery pack 5 or the second battery pack 6 has been attached to the battery box 70 (S220: YES), the microcomputer 60 proceeds to the process of S230. If the microcomputer 60 determines that the first battery pack 5 or the second battery pack 6 is not attached to the battery box 70 (S220: NO), the microcomputer 60 proceeds to the process of S240.

[0111] In S230, the microcomputer 60 sets a rotation error check flag. This causes the microcomputer 60 to determine whether or not diagnostic processing can be performed. Specifically, when the first battery pack 5 is attached to the battery box 70, the microcomputer 60 determines whether or not diagnostic processing can be performed using the first and second fault detection circuits 44, 54 before power from the first battery 5a is supplied to the motor 13. When the second battery pack 6 is attached to the battery box 70, the microcomputer 60 determines whether or not diagnostic processing can be performed using the first and second fault detection circuits 44, 54 before power from the second battery 6a is supplied to the motor 13.

[0112] Next, in S240, the microcomputer 60 determines whether the rotation error check flag is set. If the microcomputer 60 determines that the rotation error check flag is cleared (S240: NO), the microcomputer 60 proceeds to processing of S250. If the microcomputer 60 determines that the rotation error check flag is set (S240: YES), the microcomputer 60 proceeds to processing of S260.

[0113] In S250, the microcomputer 60 clears the mask count and ends this process. In S260, the microcomputer 60 increments the mask count and proceeds to the process of S270. The mask count corresponds to the time that has elapsed since the first battery pack 5 or the second battery pack 6 was attached to the battery box 70. Immediately after the first battery 5a or the second battery 6a is connected to the controller 31 and power is supplied to the controller 31, the detection accuracy of the rotation speed of the motor 13 is low. Therefore, the microcomputer 60 measures the time that has elapsed since the first battery pack 5 or the second battery pack 6 was attached to the battery box 70.

[0114] Next, in S270, the microcomputer 60 determines whether the mask count is equal to or greater than the mask time. The mask time is the time required for the detection accuracy of the rotational speed of the motor 13 to stabilize after power is supplied to the controller 31. For example, the mask time is 50 ms. If the microcomputer 60 determines that the mask count is equal to or greater than the mask time (S270: YES), the microcomputer 60 proceeds to processing of S280. If the microcomputer 60 determines that the mask count is less than the mask time (S270: NO), the microcomputer 60 ends this processing.

[0115] In S280, the microcomputer 60 determines whether the mask count is within a determination time. The determination time is the time required from when power is supplied to the controller 31 until the failure detection process for the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53 is completed. For example, the determination time is 500 ms. If the microcomputer 60 determines that the mask count has exceeded the determination time (S280: NO), the microcomputer 60 proceeds to processing of S290. If the microcomputer 60 determines that the mask count is within the determination time (S280: YES), the microcomputer 60 proceeds to processing of S300.

[0116] In S290, the microcomputer 60 clears the rotation error check flag and ends this process. In S300, the microcomputer 60 estimates the induced voltage value VmOT based on the detected rotation speed of the motor 13. The induced voltage value VmOT corresponds to the magnitude of the induced voltage generated in the windings of the motor 13 and is proportional to the rotation speed.

[0117] Next, in S310, the microcomputer 60 determines whether both the first battery pack 5 and the second battery pack 6 are attached to the battery box 70. If the microcomputer 60 determines that either the first battery pack 5 or the second battery pack 6 is attached to the battery box 70 (S310: NO), the microcomputer 60 proceeds to processing of S320. If the microcomputer 60 determines that both the first battery pack 5 and the second battery pack 6 are attached to the battery box 70 (S310: YES), the microcomputer 60 proceeds to processing of S330.

[0118] In S320, the microcomputer 60 sets the acquired first battery voltage value X1 as the reference voltage value Vref when the first battery 5a is connected to the controller 31. The microcomputer 60 sets the acquired second battery voltage value X2 as the reference voltage value Vref when the second battery 6a is connected to the controller 31. Thereafter, the microcomputer 60 proceeds to the processing of S340.

[0119] In S330, the microcomputer 60 sets the high voltage value X3 as the reference voltage value Vref. The high voltage value X3 is the higher of the first battery voltage value X1 and the second battery voltage value X2. Then, the microcomputer 60 proceeds to the process of S340.

[0120] In S340, the microcomputer 60 determines whether the induced voltage value VmOT is higher than the reference voltage value Vref. If the microcomputer 60 determines that the induced voltage value VmOT is higher than the reference voltage value Vref (S340: YES), the microcomputer 60 proceeds to processing of S350. If the microcomputer 60 determines that the induced voltage value VmOT is equal to or lower than the reference voltage value Vref (S340: NO), the microcomputer 60 ends this processing.

[0121] In S350, since there is a possibility that the induced voltage value VmOT is higher than the power supply voltage value VS5, the microcomputer 60 sets the rotation error flag and ends this process.

[0122] <1-2-3A. Another example of the decision process> Next, another example of the possibility determination process will be described with reference to Fig. 11. In this example, the microcomputer 60 executes the processes of S323 and S333 instead of the processes of S320 and S330.

[0123] In S310, if the microcomputer 60 determines that either the first battery pack 5 or the second battery pack 6 is attached to the battery box 70 (S310: NO), the microcomputer 60 proceeds to processing of S323. If the microcomputer 60 determines that both the first battery pack 5 and the second battery pack 6 are attached to the battery box 70 (S310: YES), the microcomputer 60 proceeds to processing of S333.

[0124] In S323, when the first battery 5a is connected to the controller 31, the microcomputer 60 sets the reference voltage value Vref to the sum of the first battery voltage value X1 and the boost voltage value ΔVS. When the second battery 6a is connected to the controller 31, the microcomputer 60 sets the reference voltage value Vref to the sum of the second battery voltage value X2 and the boost voltage value ΔVS. Thereafter, the microcomputer 60 proceeds to the processing of S340.

[0125] In S333, the microcomputer 60 sets the sum of the high voltage value X3 and the boost voltage value ΔVS as the reference voltage value Vref. After that, the microcomputer 60 proceeds to the process of S340. By executing S323 and S333 instead of S320 and S330, the microcomputer 60 can more accurately determine the situation in which the diagnostic process cannot be executed.

[0126] <1-2-3B. Another example of the decision process> Next, another example of the possibility determination process will be described with reference to Fig. 12. In this example, the microcomputer 60 executes the processes of S335, S345, and S355 in addition to the processes of Figs. 10A and 10B.

[0127] In S310, if the microcomputer 60 determines that either the first battery pack 5 or the second battery pack 6 is attached to the battery box 70 (S310: NO), the microcomputer 60 proceeds to processing of S320. If the microcomputer 60 determines that both the first battery pack 5 and the second battery pack 6 are attached to the battery box 70 (S310: YES), the microcomputer 60 proceeds to processing of S335.

[0128] In S335, the microcomputer 60 determines whether the first battery 5a is connected in parallel to the second battery 6a. If the microcomputer 60 determines that the first battery 5a is connected in parallel to the second battery 6a (S335: YES), the microcomputer 60 proceeds to the process of S330. If the microcomputer 60 determines that the first battery 5a is not connected in parallel to the second battery 6a (S335: NO), the microcomputer 60 proceeds to the process of S345.

[0129] In S345, the microcomputer 60 determines whether the first battery 5a is connected in series to the second battery 6a. If the microcomputer 60 determines that the first battery 5a is connected in series to the second battery 6a (S345: YES), the microcomputer 60 proceeds to the process of S355. If the microcomputer 60 determines that the first battery 5a is not connected in series to the second battery 6a (S345: NO), the microcomputer 60 proceeds to the process of S320.

[0130] In S355, the microcomputer 60 sets the sum of the first battery voltage value X1 and the second battery voltage value X2 as the reference voltage value Vref, and then proceeds to the process of S340. 10A and 10B, the microcomputer 60 executes the processes of S335, S345, and S355. As a result, even when the first battery 5a is connected in series with the second battery 6a, it is possible to determine a situation in which failures in the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53 cannot be detected.

[0131] <1-2-4. Main power supply processing> Next, the main power supply process executed by the microcomputer 60 in S20 will be described with reference to the flowchart of FIG.

[0132] In S400, the microcomputer 60 determines whether the main power supply is off. If the microcomputer 60 determines that the main power supply is off (S400: YES), the microcomputer 60 proceeds to processing of S410. If the microcomputer 60 determines that the main power supply is on (S400: NO), the microcomputer 60 proceeds to processing of S450.

[0133] In S410, the microcomputer 60 determines whether the rotation error flag is set. If the microcomputer 60 determines that the rotation error flag is cleared (S410: NO), the microcomputer 60 proceeds to processing of S420. If the microcomputer 60 determines that the rotation error flag is set (S410: YES), the microcomputer 60 proceeds to processing of S440.

[0134] In S420, the microcomputer 60 determines whether the failure error flag is set. If the microcomputer 60 determines that the failure error flag is cleared (S420: NO), the microcomputer 60 proceeds to processing of S430. If the microcomputer 60 determines that the failure error flag is set (S420: YES), the microcomputer 60 proceeds to processing of S440.

[0135] In S430, the microcomputer 60 determines whether to switch the main power state from OFF to ON based on the user's switch operation. Specifically, the microcomputer 60 determines whether the main power switch 92 was pressed while the brake lever 18 was being pulled. If the microcomputer 60 determines that the main power switch 92 was pressed while the brake lever 18 was being pulled, it switches the main power state from OFF to ON. Otherwise, the microcomputer 60 maintains the main power state as OFF. Then, the microcomputer 60 ends this process.

[0136] In S440, the microcomputer 60 switches the main power supply state from OFF to ON. That is, the microcomputer 60 changes the main power supply state without the user operating the main power switch 92. The microcomputer 60 turns ON the main power supply state and supplies power to the LED and / or buzzer 68 to notify the user that the electric operating machine 1 is in an error state via the LED and / or buzzer 68. Thereafter, the microcomputer 60 ends this process.

[0137] In S450, the microcomputer 60 determines whether the rotation error flag or the malfunction error flag is set. If the microcomputer 60 determines that the rotation error flag or the malfunction error flag is set (S450: YES), the microcomputer 60 ends this process. That is, the microcomputer 60 keeps the main power supply on to notify the LED and / or buzzer 68 that the electric work machine 1 is in an error state, and ends this process. If the microcomputer 60 determines that the rotation error flag and the malfunction error flag are cleared (S450: NO), the microcomputer 60 proceeds to the process of S460.

[0138] In S460, the microcomputer 60 determines whether to switch the main power state from on to off based on the user's switch operation. Specifically, the microcomputer 60 determines whether the main power switch 92 was pressed while the brake lever 18 was being pulled. If the microcomputer 60 determines that the main power switch 92 was pressed while the brake lever 18 was being pulled, it switches the main power state from on to off. Otherwise, the microcomputer 60 maintains the main power state as on.

[0139] Next, in S470, if the main power state is on and there is no user operation for a predetermined time or longer, the microcomputer 60 automatically switches the main power state from on to off. The microcomputer 60 turns off the main power state and transitions to an energy-saving state. Then, the microcomputer 60 ends this process.

[0140] <1-2-5. Notification processing> Next, the notification process executed by the microcomputer 60 in S30 will be described with reference to the flowchart of FIG.

[0141] In S500, the microcomputer 60 determines whether the main power supply is on. If the microcomputer 60 determines that the main power supply is off (S500: NO), the microcomputer 60 proceeds to processing of S510. If the microcomputer 60 determines that the main power supply is on (S500: YES), the microcomputer 60 proceeds to processing of S520.

[0142] In S510, the microcomputer 60 turns off all displays of the electric working machine 1. That is, the microcomputer 60 turns off all LEDs of the electric working machine 1. In S520, the microcomputer 60 determines whether the rotation error flag is set. If the microcomputer 60 determines that the rotation error flag is set (S520: YES), the microcomputer 60 proceeds to processing of S530. If the microcomputer 60 determines that the rotation error flag is cleared (S520: NO), the microcomputer 60 proceeds to processing of S540.

[0143] In S530, the microcomputer 60 notifies the user that a rotation error has occurred. Specifically, the microcomputer 60 changes the color of the LED of the main power switch 92. For example, the microcomputer 60 (i) changes the color of the LED of the main power switch 92 from green to red. The microcomputer 60 also (ii) blinks the LED of the speed mode display unit 97 and / or the forward / reverse display unit 95. Furthermore, the microcomputer 60 (iii) continues to sound the buzzer 68 continuously. Note that the microcomputer 60 does not need to execute all of the above (i) to (iii), and it is sufficient to execute at least one of (i) to (iii).

[0144] In S540, the microcomputer 60 determines whether the failure error flag is set. If the microcomputer 60 determines that the failure error flag is set (S540: YES), the microcomputer 60 proceeds to processing of S550. If the microcomputer 60 determines that the failure error flag is cleared (S540: NO), the microcomputer 60 proceeds to processing of S560.

[0145] In S550, the microcomputer 60 notifies the user that a malfunction error has occurred. Specifically, the microcomputer 60 (iv) changes the color of the LED of the main power switch 92 from green to red. The microcomputer 60 also (v) blinks the LED of the speed mode display unit 97 and / or the forward / reverse display unit 95. The microcomputer 60 may change the blinking pattern to the blinking pattern (ii) described above. The microcomputer 60 also (vi) continuously sounds the buzzer 68. The microcomputer 60 may change the sounding pattern of the buzzer 68 to the sounding pattern (iii) described above. The microcomputer 60 does not need to execute all of the above (iv) to (vi), and may execute at least one of the above (iv) to (vi).

[0146] In S560, the microcomputer 60 notifies that the electric work machine 1 is in a normal state. Specifically, the microcomputer 60 lights up the LEDs of the main power switch 92, the speed mode display unit 97, the forward / reverse display unit 95, and the remaining capacity display units 72A and 72B depending on the states of the electric work machine 1, the first battery pack 5, and the second battery pack 6.

[0147] In this embodiment, the process of notifying that a rotation error has occurred (S530) corresponds to an example of a general abnormality process in the embodiment. Also, in this embodiment, the main power switch 92, the speed mode display unit 97, the forward / reverse display unit 95, and the buzzer 68 correspond to an example of a general notification unit in the embodiment.

[0148] <1-2-6. Motor control processing> Next, the motor control process executed by the microcomputer 60 in S40 will be described with reference to the flowchart of FIG.

[0149] In S600, the microcomputer 60 determines whether the main power supply is on. If the microcomputer 60 determines that the main power supply is off (S600: NO), the microcomputer 60 proceeds to processing of S610. If the microcomputer 60 determines that the main power supply is on (S600: YES), the microcomputer 60 proceeds to processing of S620.

[0150] In S610, the microcomputer 60 outputs a stop signal to the motor drive circuit 61 to shut off all outputs of the motor drive circuit 61. That is, the microcomputer 60 stops the supply of power to the motor 13. Specifically, the microcomputer 60 turns off all switching elements of the motor drive circuit 61. Thereafter, the microcomputer 60 ends this process.

[0151] In S620, the microcomputer 60 determines whether the rotation error flag is set. If the microcomputer 60 determines that the rotation error flag is cleared (S620: NO), the microcomputer 60 proceeds to processing of S630. If the microcomputer 60 determines that the rotation error flag is set (S620: YES), the microcomputer 60 proceeds to processing of S640.

[0152] In S630, the microcomputer 60 determines whether the failure error flag is set. If the microcomputer 60 determines that the failure error flag is cleared (S630: NO), the microcomputer 60 proceeds to processing of S650. If the microcomputer 60 determines that the failure error flag is set (S630: YES), the microcomputer 60 proceeds to processing of S640.

[0153] In S640, the microcomputer 60 outputs a drive signal to the motor drive circuit 61 to apply an electric brake (specifically, a short-circuit brake) to the motor 13. Specifically, the microcomputer 60 turns off the three high-side switching elements of the motor drive circuit 61 and turns on the three low-side switching elements. Thereafter, the microcomputer 60 ends this process.

[0154] In S650, the microcomputer 60 executes a process for driving the motor 13. Specifically, the microcomputer 60 sets a target rotation speed or an output duty ratio according to the speed mode and the distance the drive lever 91 is pulled. Then, the microcomputer 60 generates a drive signal so that the actual rotation speed of the motor 13 becomes the target rotation speed. Alternatively, the microcomputer 60 generates a PWM signal having an output duty ratio as the drive signal. Then, the microcomputer 60 outputs the drive signal to the motor drive circuit 61 to rotate the motor 13. After that, the microcomputer 60 ends this process.

[0155] In this embodiment, the process of applying the electric brake to the motor 13 (S640) corresponds to an example of the general abnormality process of the embodiment.

[0156] <1-3.Effects> According to the first embodiment described above in detail, the following effects are achieved.

[0157] (1) The microcomputer 60 notifies the occurrence of a rotation error without performing a short-circuit detection process based on the induced voltage value VmOT being greater than the reference voltage value Vref. Therefore, when there is a possibility that a short circuit in the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53 cannot be detected, the microcomputer 60 can take appropriate action without performing a diagnostic process.

[0158] (2) The microcomputer 60 can calculate the induced voltage value VmOT from the actual rotation speed of the motor 13. Then, the microcomputer 60 can determine whether or not a failure in the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53 can be detected by comparing the induced voltage value VmOT with the reference voltage value Vref.

[0159] (3) When the motor 13 is generating power, the microcomputer 60 can stop the power generation of the motor 13 by applying a short-circuit brake to the motor 13. This reduces the induced voltage value VmOT, and the microcomputer 60 can detect failures in the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53.

[0160] (4) When there is a possibility that the microcomputer 60 cannot detect a failure in the diode D1, the first switching circuit 43, the diode D2, or the second switching circuit 53, the microcomputer 60 notifies the user of the occurrence of an abnormality via the LED and / or the buzzer 68. This allows the user to recognize that an abnormality has occurred in the electric operating machine 1.

[0161] (5) The microcomputer 60 sets the sum of the high voltage value X3 and the boost voltage value ΔVS as the reference voltage value Vref, and compares the induced voltage value VmOT with the reference voltage value Vref. This allows the microcomputer 60 to accurately determine whether or not a failure in the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53 can be detected.

[0162] (6) When the first battery 5a and the second battery 6a are attached to the electric work machine 1, the microcomputer 60 sets the high voltage value X3 to the reference voltage value Vref. This enables the microcomputer 60 to more accurately determine whether or not a failure in the diode D1, the first switching circuit 43, the diode D2, and the second switching circuit 53 can be detected.

[0163] (2. Second Embodiment) <2-1. Differences from the first embodiment> The second embodiment has the same basic configuration as the first embodiment, so differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and reference will be made to the preceding description.

[0164] The second embodiment differs from the first embodiment in that the microcomputer 60 executes a switch control process in addition to the processes of S10 to S40 in the main process according to the first embodiment. The power supply voltage of the switch drive circuits 43c, 53c of the switching elements 43a, 53a corresponds to the voltage difference Vdd between the voltage obtained by boosting the high voltage X3 and the voltage VS6 of the capacitor 62. The voltage VS6 is equal to the induced voltage VmOT generated in the motor 13. Therefore, as shown in FIG. 18, as the induced voltage VmOT increases, the voltage difference Vdd decreases. When the voltage difference Vdd falls below a predetermined value, the protection function of the switch drive circuits 43c, 53c is activated, and the first and second input signals output from the switch drive circuits 43c, 53c are turned off (i.e., low level). This turns off the switching elements 43a, 53a, and stops the supply of power from the first battery 5a or the second battery 6a to the motor 13. When the power supply voltage drops, the conduction loss of the switching elements included in the switch drive circuits 43c, 53c increases. Therefore, in order to prevent damage to the switching elements, the switch drive circuits 43c and 53c activate a protection function when the power supply voltage drops.

[0165] If a user pushes the electric work machine 1 down a slope while working with the electric work machine 1, the actual rotational speed of the motor 13 increases. Consequently, the induced voltage value VmOT of the motor 13 increases, and the voltage difference Vdd decreases. As a result, the protective function of the switch drive circuits 43c and 53c may be activated during work, causing the motor 13 to stop. If the protective function of the switch drive circuits 43c and 53c is activated, the protective function cannot be released unless the first and second switching signals are turned off. However, the microcomputer 60 cannot determine whether the protective function of the switch drive circuits 43c and 53c is activated. Therefore, the microcomputer 60 may continue to turn on the first and second switching signals, preventing the protective function of the switch drive circuits 43c and 53c from being released and preventing the motor 13 from being restarted. Therefore, in this embodiment, the microcomputer 60 executes a switch control process to prevent the motor 13 from being unable to be restarted during work.

[0166] <2-2. Switch control processing> The switch control process executed by the microcomputer 60 will be described with reference to Fig. 16. The microcomputer 60 executes this process after the process of S40 in the main process.

[0167] In S700, the microcomputer 60 determines whether the motor 13 can be driven. Specifically, the microcomputer 60 determines whether the motor 13 can be driven based on the distance the drive lever 91 has been pulled, the state of the first battery 5a, the state of the second battery 6a, etc. If the microcomputer 60 determines that the motor 13 cannot be driven (S700: NO), the microcomputer 60 proceeds to processing of S710. If the microcomputer 60 determines that the motor 13 can be driven (S700: YES), the microcomputer 60 proceeds to processing of S730.

[0168] In S710, the microcomputer 60 clears the timer to zero. Next, in S720, the microcomputer 60 turns off the first and second switch signals. That is, the microcomputer 60 sets the first and second switch signals to a low level. As a result, the input signals output from the switch drive circuits 43c and 53c are turned off (i.e., to a low level). Consequently, the switching elements 43a and 53a are turned off. Thereafter, the microcomputer 60 ends this process.

[0169] In S730, the microcomputer 60 increments the timer, which corresponds to the time during which the first and second switch signals are in the ON state. Next, in S740, the microcomputer 60 determines whether the timer is shorter than the time threshold. The time threshold corresponds to the time it takes for the switching elements 43a and 53a to change from off to on and for an inrush current to flow through the capacitor 62. For example, the time threshold is 5 ms. If the microcomputer 60 determines that the timer is shorter than the time threshold (S740: YES), the microcomputer 60 proceeds to processing of S750. If the microcomputer 60 determines that the timer is equal to or greater than the time threshold (S740: NO), the microcomputer 60 proceeds to processing of S760.

[0170] In S750, the microcomputer 60 turns on the first and second switch signals (i.e., to a high level), and ends this process. In S760, the microcomputer 60 determines whether the first and second switch signals are on. If the microcomputer 60 determines that the first and second switch signals are on (S760: YES), the microcomputer 60 proceeds to processing of S770. If the microcomputer 60 determines that the first and second switch signals are off (S760: NO), the microcomputer 60 proceeds to processing of S790.

[0171] In S770, the microcomputer 60 determines whether the voltage difference Vdd is decreasing and whether the protective operation of the switch drive circuits 43c, 53c is about to be activated. Specifically, the microcomputer 60 determines whether (i) the voltage difference obtained by subtracting the high voltage value X3 from the induced voltage value VmOT is greater than the first voltage threshold Vth1, and (ii) the battery current value Ib is smaller than the current threshold Ith. The battery current value Ib corresponds to the magnitude of the battery current flowing from the first battery 5a or the second battery 6a to the motor 13.

[0172] Condition (i) corresponds to the voltage difference Vdd being slightly greater than a predetermined value. Condition (ii) corresponds to the motor 13 generating power and therefore no battery current flowing. For example, the first voltage threshold Vth1 is 1.5 V. The current threshold Ith is 0.5 A. If the microcomputer 60 determines that conditions (i) and (ii) are met (YES at S770), the microcomputer 60 proceeds to processing at S780. If the microcomputer 60 determines that conditions (i) or (ii) are not met (NO at S770), the microcomputer 60 proceeds to processing at S790. Note that in another embodiment, the microcomputer 60 may not consider condition (ii) at S770. If the microcomputer 60 determines that condition (i) is met, the microcomputer 60 may proceed to processing at S780, and if the microcomputer 60 determines that condition (i) is not met, the microcomputer 60 may proceed to processing at S790.

[0173] In S780, the microcomputer 60 turns off the first and second switch signals. That is, the microcomputer 60 turns off the input signals (i.e., to low level) before the protection functions of the switch drive circuits 43c and 53c are activated. Thereafter, the microcomputer 60 ends this process.

[0174] In S790, the microcomputer 60 determines whether (iii) the voltage difference obtained by subtracting the high voltage value X3 from the induced voltage value VmOT is smaller than the second voltage threshold value Vth2. Condition (iii) corresponds to the actual rotation speed decreasing and the voltage difference Vdd becoming sufficiently small. For example, the second voltage threshold value Vth2 is 0.5 V. If the microcomputer 60 determines that the condition (iii) is met, it proceeds to processing in S800. If the microcomputer 60 determines that the condition (iii) is not met, it ends this processing.

[0175] In S800, the microcomputer 60 turns on the first and second switch signals. This turns on the input signals to the switch drive circuits 43c and 53c. This in turn turns on the switching elements 43a and 53a, and the supply of power from the first battery 5a or the second battery 6a to the motor 13 is resumed. Next, the microcomputer 60 clears the timer to 0 and ends this process.

[0176] <2-3. Operation> 17 shows the changes over time in the actual rotation speed, duty ratio, first battery voltage value X1, induced voltage value VmOT, and first switch signal when the microcomputer 60 executes the switch control process. Here, the case where only the first battery 5a is connected to the controller 31 will be described.

[0177] At time t1, the first switch signal changes from off to on, and the actual rotation speed and duty ratio increase. When the actual rotation speed reaches the target rotation speed, the duty ratio becomes constant.

[0178] At time t2, the electric work machine 1 starts to descend the slope, the actual rotation speed starts to increase, and the duty ratio starts to decrease. At time t3, the motor 13 starts to generate power, and the induced voltage value VmOT starts to increase.

[0179] At time t4, the voltage difference between the induced voltage value VmOT and the battery voltage value X1 exceeds the first voltage threshold Vth1, and the first switch signal changes from ON to OFF. This stops the supply of power from the first battery 5a to the motor 13. Therefore, at time t5, the actual rotational speed starts to decrease, and the induced voltage value VmOT also starts to decrease.

[0180] At time t6, the voltage difference between the induced voltage value VmOT and the battery voltage value X1 becomes less than the second voltage threshold value Vth2, and the first switch signal changes from OFF to ON. This restarts the supply of power from the first battery 5a to the motor 13. Therefore, at time t6, the actual rotation speed and the duty ratio start to increase.

[0181] <2-4. Effects> According to the second embodiment described above in detail, in addition to the effects (1) to (6) of the first embodiment described above, the following effect is also achieved.

[0182] (7) When the motor 13 starts generating power while it is being driven and the induced voltage value VmOT exceeds the sum of the high voltage value X3 and the first voltage threshold value Vth1, the microcomputer 60 turns off the switching elements 43a and 53a. This reduces the rotation speed of the motor 13 and prevents the protection function of the switch drive circuits 43c and 53c from being activated.

[0183] (8) The microcomputer 60 can prevent the protection function of the switch drive circuits 43c and 53c from being activated by turning off the first and second switch signals and turning off the input signals to the switch drive circuits 43c and 53c.

[0184] (9) When the induced voltage value becomes smaller than the battery voltage value, the microcomputer 60 turns on the input signal, thereby restarting the supply of power from the battery to the motor.

[0185] (3. Other Embodiments) Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0186] (a) In each of the above embodiments, the electric working machine 1 is configured to be able to mount two battery packs, but it may also be configured to be able to mount only one battery pack. Alternatively, the electric working machine 1 may be configured to be able to mount three or more battery packs.

[0187] (b) In each of the above embodiments, the microcomputer 60 obtains the induced voltage value VmOT from the actual rotational speed of the motor 13. However, the induced voltage value Vmot of the motor 13 may be measured by a voltage measurement circuit. Specifically, the electric work machine 1 may include a voltage measurement circuit configured to detect the voltage value of the winding of each phase of the motor 13. The voltage measurement circuit of each phase measures the voltage value of the winding of each phase and outputs a measurement signal indicating the measured voltage value to the microcomputer 60. The microcomputer 60 obtains the induced voltage value VmOT based on the measurement signal. In this case, the voltage measurement circuit corresponds to an example of an overall detection unit in the embodiments, and the voltage value measured by the voltage measurement circuit corresponds to an example of an overall voltage-related value in the embodiments.

[0188] (c) In each of the above embodiments, the main power switch 92, the speed mode display 97, the LEDs of the forward / reverse display 95, and the buzzer 68 may be connected to the first discharge path 81 closer to the first battery 5a than the diode D1. Alternatively, these LEDs and the buzzer 68 may be connected to the second discharge path 82 closer to the second battery 6a than the diode D2. When connected in this manner, these LEDs and the buzzer 68 can receive power from the first battery 5a or the second battery 6a even when the main power supply is off. Therefore, the microcomputer 60 can execute the process of S530 without executing the process of S440.

[0189] (d) In each of the above embodiments, the microcontroller 60 may be a combination of various individual electronic components, an Application Specified Integrated Circuit (ASIC), an Application Specific Standard Product (ASSP), a programmable logic device such as a Field Programmable Gate Array (FPGA), or a combination of these.

[0190] (e) In the second embodiment, the microcomputer 60 may turn off the power supplies to the switch drive circuits 43c and 53c in the process of S780 instead of turning off the first and second switch signals. By turning off the power supplies to the switch drive circuits 43c and 53c, the microcomputer 60 can prevent the protection function of the switch drive circuits 43c and 53c from being activated. Furthermore, the microcomputer 60 may turn on the power supplies to the switch drive circuits 43c and 53c in the process of S800 instead of turning on the first and second switch signals. By turning on the power supplies to the switch drive circuits 43c and 53c, the microcomputer 60 can resume the supply of power from the first battery 5a or the second battery 6a to the motor 13.

[0191] (f) Multiple functions of one component in the above embodiments may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Explanation of symbols]

[0192] 1...electric work machine, 5...first battery pack, 6...second battery pack, 5a...first battery, 6a...second battery, 13...motor, 14...rotation sensor, 31...controller, 41, 51...boost circuit, 43...first switching circuit, 53...second switching circuit, 43a, 53a...switching element, 43b, 53b...AND circuit, 43c, 53c...switch drive circuit, 44...first fault detection circuit, 54...second fault detection circuit, 60...microcomputer, 61...motor drive circuit, 68...buzzer, 70...battery box, 72A, 72B...remaining capacity display unit, 81...first discharge path, 82...second discharge path, 91...drive lever, 92...main power switch, 95...forward / reverse display unit, 97...speed mode display unit.

Claims

1. A motor; a motor drive circuit configured to control a current through the motor; a detection unit configured to detect a voltage-related value related to a voltage of the motor; a first mounting portion configured to mount a first battery; a first discharge path connecting the first mounting portion to the motor drive circuit; a first switching unit disposed on the first discharge path and configured to be in a conductive state for conducting the first discharge path or in a cut-off state for cutting off the first discharge path; a control unit configured to control the first switching unit and the motor drive circuit to supply power from the first battery to the motor, based on the first battery being attached to the first attachment portion, before supplying power from the first battery to the motor, an induced voltage value corresponding to a magnitude of an induced voltage generated in the motor is obtained from the voltage-related value detected by the detection unit; executing a diagnostic process for diagnosing a failure of the first switching unit based on the induced voltage value being equal to or less than a threshold value; and executing an abnormality process different from the diagnosis process based on the induced voltage value being greater than the threshold value. and a control unit configured to Electric work equipment.

2. the voltage-related value is the rotational speed of the motor; the threshold value is a first voltage value corresponding to the magnitude of the output of the first battery; The electric operating machine according to claim 1 .

3. the abnormality processing includes applying a short-circuit brake to the motor via the motor drive circuit. The electric operating machine according to claim 1 or 2.

4. Further provided with a notification unit, The abnormality processing includes notifying, via the notification unit, that an abnormality has occurred in the electric operating machine. The electric operating machine according to any one of claims 1 to 3.

5. a faulty battery detection circuit configured to receive an operating voltage and detect a fault in the first switching unit; the operating voltage is a voltage boosted from the voltage of the first battery, The threshold value is a voltage value corresponding to the magnitude of the operating voltage. The electric operating machine according to any one of claims 1 to 4.

6. a second mounting portion configured to mount a second battery; a second discharge path connecting the second mounting portion to the motor drive circuit; a second switching unit that is disposed on the second discharge path and configured to be in a conductive state that makes the second discharge path conductive or in a cut-off state that cuts off the second discharge path, The control unit a power supply circuit configured to supply power from the first battery and / or the second battery to the motor by controlling the first switching unit, the second switching unit, and the motor drive circuit; The control unit acquiring the induced voltage value before supplying electric power from the first battery and the second battery to the motor based on the first battery being attached to the first attachment portion and the second battery being attached to the second attachment portion; comparing a first voltage value corresponding to the magnitude of the output of the first battery with a second voltage value corresponding to the magnitude of the output of the second battery; setting the larger of the first voltage value and the second voltage value as the threshold value; The electric operating machine according to any one of claims 1 to 5.

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