Electric power shovel and control method

Abstract

The present application provides an electric working machine and a control method. The electric working machine is provided with a motor and a control circuit. The motor is provided with a stator and a rotor. The control circuit is configured to control the motor in such a manner that a current corresponding to a current command value flows into the stator. The control circuit is configured to, in a d-q coordinate system having a d-axis and a q-axis that are orthogonal to each other, set the current command value in a region that is more toward a positive side of the q-axis than both a constant torque curve and a maximum flux efficiency curve, in a case where a measured value of a q-axis component of the current is included in a region that is more toward a positive side of the q-axis than an intersection of the constant torque curve and the maximum flux efficiency curve.

Description

Technical Field

[0001] This invention relates to an electric work machine. Background Technology

[0002] As a control method for brushless motors, vector control is known, which controls the current vector by taking into account factors such as rotor orientation or rotational speed in order to effectively generate torque. For example, Japanese Patent No. 7257647 discloses an electric tool that combines weak excitation control with vector control.

[0003] Weak excitation control is a technique that, in the high-speed rotation region of the motor, when the maximum speed is reduced because the reverse voltage is equal to the power supply voltage, suppresses the reverse power by partially offsetting the magnetic flux of the rotor's permanent magnets, thereby achieving high-speed rotation. Summary of the Invention

[0004] When switching from weak excitation control to normal vector control, the output based on the motor's rotational speed and torque can sometimes become unstable due to the drastic change in the current vector.

[0005] One aspect of this invention aims to provide a technique for stabilizing the output of a motor in vector control of a motor.

[0006] One aspect of the present invention relates to an electric work machine comprising a motor and a control circuit. The motor comprises a stator and a rotor, and is configured to receive power from a power source and be driven. The stator is configured to generate a magnetic field through the flow of current. The rotor has a magnetic body and is configured to rotate about a rotation axis in response to changes in the magnetic field. The current has a d-axis component as a d-axis component and a q-axis component as a q-axis component in a d-q coordinate system having mutually orthogonal d-axis and q-axis. The control circuit is configured to control the motor by causing a current corresponding to a current command value to flow into the stator. The control circuit is configured to set the current command value in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve, provided that the measured value of the q-axis component is located in a region closer to the positive side of the q-axis than the intersection of the defined constant torque curve and the maximum flux efficiency curve. In the d-q coordinate system, the maximum flux efficiency curve is the set of points where the maximum torque per unit flux is obtained.

[0007] With this configuration, when switching from weak excitation control to normal vector control, the current command value is set in the direction that does not reduce torque. This ensures stable motor output.

[0008] In one aspect of the invention, the control circuit can be configured such that, when the measured value of the q-axis component is located in a region closer to the positive side of the q-axis than the intersection of the predetermined constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than both the predetermined constant torque curve and the maximum flux efficiency curve, and closer to the negative side of the q-axis than the maximum current efficiency curve. In the d-q coordinate system, the maximum current efficiency curve can be the set of points where the maximum torque per unit current is obtained.

[0009] Based on this configuration, the current command value is set to not exceed the maximum current efficiency curve. This helps to suppress the decrease in motor output efficiency.

[0010] One aspect of the present invention relates to an electric work machine comprising a motor and a control circuit. The motor comprises a stator and a rotor, and is configured to receive power from a power source and be driven. The stator is configured to generate a magnetic field through the flow of current. The rotor has a magnetic body and is configured to rotate about a rotation axis in response to changes in the magnetic field. The control circuit is configured to switch between multiple modes, including a first mode, a second mode, and a third mode, and operate in one of these modes to control the motor by causing a current corresponding to a current command value to flow into the stator. In the first mode, the control circuit sets the current command value to maximize torque per unit current. In the second mode, the control circuit sets the current command value to generate a magnetic field in the direction that counteracts the magnetic flux generated by the magnetic body. When switching from the second mode to the first mode, the control circuit operates via the third mode.

[0011] The control circuit is configured such that, when transitioning from mode 2 to mode 3, the measured value of the current flowing through the stator and the current command value are saved as a reference measured value and a reference command value, respectively. The control circuit is configured to set the current command value in mode 3 based on at least one of the reference measured value and the reference command value.

[0012] Based on this configuration, in the third mode, which is the transition between the second mode (equivalent to weak excitation control) and the first mode (equivalent to normal vector control), the current command value is set based on the reference measured value and the reference command value. This suppresses abrupt changes in the current vector, thereby stabilizing the motor output.

[0013] In one aspect of the present invention, the control circuit may be configured to set the current command value in the third mode based on the difference between the reference measured value and the measured value of the current, and the reference command value.

[0014] Based on this configuration, when switching from the second mode, which is equivalent to weak excitation control, to the first mode, which is equivalent to normal vector control, the current command value is set based on the difference between the reference measured value and the measured current value, in addition to the reference command value. This allows the motor output to remain stable.

[0015] In one aspect of the invention, the current can have a d-axis component as the d-axis component and a q-axis component as the q-axis component in a d-q coordinate system having mutually orthogonal d-axis and q-axis. The control circuit can be configured to migrate from the second mode to the third mode when the measured value of the q-axis component reaches or exceeds a predetermined threshold.

[0016] Based on this configuration, the operating mode can be switched according to the measured value of the q-axis component. Therefore, the motor can be controlled in the optimal operating mode corresponding to the measured value of the q-axis component.

[0017] In one aspect of the invention, the control circuit can be configured such that, in the third mode, the current command value is set in a region of the d-q coordinate system that is closer to the positive side of the q axis than the constant torque curve.

[0018] Based on this configuration, when switching from the second mode, which is equivalent to weak excitation control, to the first mode, which is equivalent to normal vector control, the current command value is set in a direction that does not reduce torque. As a result, the motor output can be stabilized.

[0019] In one aspect of the invention, the control circuit can be configured to migrate between multiple modes based on the measured values ​​of the q-axis component.

[0020] Based on this configuration, the motor can be controlled in the optimal operating mode corresponding to the measured value of the q-axis component.

[0021] In one aspect of the invention, the control circuit may also use the d-axis component of the current command value to perform constant rotation control to maintain the motor speed at a constant rate.

[0022] Based on this configuration, an appropriate current vector is set based on both the q-axis component and the d-axis component of the current command value, thereby enabling constant rotation control.

[0023] In one aspect of the invention, constant rotation control may include a process that reduces the d-axis component of the current command value.

[0024] In one aspect of the invention, constant rotation control may include a process of reducing the d-axis component of the current command value so as to set the current command value within the region of the induced voltage limiting ellipse in the d-q coordinate system.

[0025] Based on this configuration, in constant rotation control, the decrease in the q-axis component of the current command value can be suppressed. Therefore, in constant rotation control, the decrease in torque can be suppressed.

[0026] In one aspect of the present invention, the control circuit may be configured to acquire a measured value of the power supply current supplied from the power source and an upper limit value of the power supply current. The control circuit may also be configured to calculate an upper limit value of the d-axis component of the current command value based on the measured value of the power supply current and the upper limit value of the power supply current.

[0027] In one aspect of the present invention, the control circuit can be configured to calculate the upper limit of the d-axis component of the current command value by multiplying the value obtained by adding 1 to the difference between the measured value of the power supply current and the upper limit value of the power supply current by the measured value of the d-axis component of the current.

[0028] Based on this configuration, the upper limit of the d-axis component of the current command value can be dynamically calculated based on the measured value of the power supply current, without exceeding the upper limit of the power supply current.

[0029] One aspect of the present invention relates to an electric work machine comprising: a motor and a control circuit. The motor has a stator and a rotor, and is configured to receive power from a power source and be driven. The stator is configured to generate a magnetic field through the flow of current. The rotor has a magnetic body and is configured to rotate about a rotation axis in response to changes in the magnetic field. The control circuit is configured to switch between multiple modes, including a first mode, a second mode, and a third mode, and operate in one of these modes to control the motor such that a current corresponding to a current command value flows into the stator. In the first mode, the control circuit sets the current command value to maximize torque per unit current. In the second mode, the control circuit sets the current command value to generate a magnetic field in the direction that cancels the magnetic flux generated by the magnetic body. When switching from the second mode to the first mode, the control circuit operates via the third mode. In the third mode, the control circuit sets the current command value to increase the motor torque while decreasing the motor speed.

[0030] Based on this configuration, when switching from the second mode, which is equivalent to weak excitation control, to the first mode, which is equivalent to normal vector control, a sharp decrease in motor output can be suppressed. This allows the motor output to remain stable.

[0031] One aspect of the present invention relates to a control method for controlling a motor having a stator and a rotor, comprising the following steps: controlling the motor such that a current corresponding to a current command value flows into the stator; and setting the current command value in a d-q coordinate system having mutually orthogonal d-axis and q-axis, where the measured value of the q-axis component, which is the q-axis component of the current, is contained in a region closer to the positive side of the q-axis than the intersection of a predetermined constant torque curve and a maximum flux efficiency curve, in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve. In the d-q coordinate system, the maximum flux efficiency curve is the set of points where the maximum torque per unit flux is obtained.

[0032] According to this control method, the same effect as the electric work machine mentioned above can be achieved.

[0033] One aspect of the present invention is a control method for controlling a motor having a stator and a rotor, comprising the following steps: controlling the motor such that a current corresponding to a current command value flows into the stator; transitioning between multiple modes including a first mode, a second mode, and a third mode, operating in one of the multiple modes, and controlling the motor such that a current corresponding to the current command value flows into the stator; in the first mode, setting the current command value such that the torque per unit current is maximized; in the second mode, setting the current command value such that a magnetic field is generated in the direction of canceling the magnetic flux generated by a magnetic body; when transitioning from the second mode to the first mode, operating via the third mode; and in the third mode, setting the current command value in a region in the d-q coordinate system that is closer to the positive side of the q-axis than the constant torque curve.

[0034] According to this control method, the same effect as the electric work machine mentioned above can be achieved. Attached Figure Description

[0035] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] Figure 1 It is a 3D diagram of an electric work machine.

[0037] Figure 2 This is a diagram used to illustrate the electrical configuration of an electric work machine.

[0038] Figure 3 It is a diagram used to illustrate the electrical configuration of a control circuit.

[0039] Figure 4 This is a diagram used to illustrate the processing of the limit value calculation unit.

[0040] Figure 5This is a flowchart representing the interrupt handling performed by the control circuit.

[0041] Figure 6 It is a state transition diagram that represents the operating mode of the control circuit.

[0042] Figure 7 This is a flowchart representing the weak excitation control process.

[0043] Figure 8 This is a flowchart representing the MTPA process.

[0044] Figure 9 This is a flowchart representing the weak excitation process.

[0045] Figure 10 This is a flowchart representing the processing during the migration.

[0046] Figure 11 This is a flowchart representing the regeneration process.

[0047] Figure 12 It is a diagram used to illustrate the current trajectory in the d-q coordinate system.

[0048] Figure 13 It is a diagram used to illustrate N-T characteristics.

[0049] Figure 14 It is a diagram used to illustrate the T-N and I-N characteristics.

[0050] Figure 15 This is a diagram illustrating the mechanical structure of the electric work machine, including the motor, power transmission unit, and saw chain, in the second embodiment.

[0051] Figure 16 This is a diagram illustrating the diameter of the motor and the stacking thickness of the stator in the electric work machine of the second embodiment.

[0052] Figure 17 This is a diagram illustrating the actual N-T characteristics, actual P-T characteristics, actual I-T characteristics, and actual V-T characteristics of the electric work machine in the second embodiment when controlled in the first embodiment for a motor with a maximum output of approximately 2 to 3 [kW].

[0053] Figure 18 This is a diagram illustrating the actual N-T characteristics, actual P-T characteristics, actual I-T characteristics, and actual V-T characteristics of the electric work machine in the second embodiment when controlled in the first embodiment for a motor with a maximum output of approximately 3 to 4 [kW].

[0054] Figure 19 This is a perspective view of the electric work machine in the third embodiment, viewed from the cutter side.

[0055] Figure 20 This is a perspective view of the electric work machine in the third embodiment as viewed from the outer casing side.

[0056] Figure 21 This is a perspective view of the electric work machine in the third embodiment when the outer casing and motor are removed.

[0057] Figure 22 This is a cross-sectional view of the electric work machine in the third embodiment, including the cooling fan, perpendicular to the left-right direction.

[0058] Figure 23 This is a cross-sectional view of the electric work machine in the third embodiment, including the motor and the power transmission unit, perpendicular to the front-to-back direction.

[0059] Figure 24 This is a diagram used to illustrate the actual N-T characteristics, actual P-T characteristics, actual I-T characteristics, and actual V-T characteristics of the motor when the motor is controlled in the third embodiment.

[0060] Figure 25 This is a diagram illustrating the actual N-T characteristics, actual P-T characteristics, actual I-T characteristics, and actual V-T characteristics of the tool side driven by the motor when the control is performed with respect to the motor in the third embodiment.

[0061] Figure 26 It is a diagram used to illustrate the current trajectory in the d-q coordinate system with a positive slope in other embodiments.

[0062] Figure 27 This is a diagram used to illustrate the current trajectory in the d-q coordinate system with a negative slope in other embodiments.

[0063] Figure 28 This is a diagram used to illustrate the current trajectory in the d-q coordinate system when migrating directly from the induced voltage limiting ellipse to the MTPA curve in other embodiments. Detailed Implementation

[0064] 1. Overview of Implementation Methods

[0065] One embodiment provides an electric work machine. The electric work machine may have at least one of the following features.

[0066] Feature 1: The electric work machine is equipped with a motor.

[0067] Feature 2: The motor has a stator.

[0068] Feature 3: The motor has a rotor.

[0069] Feature 4: The motor is configured to receive power from a power source and be driven.

[0070] Feature 5: The electric work machine has a control circuit.

[0071] Feature 6: The stator is configured to generate a magnetic field through the flow of electric current.

[0072] Feature 7: The rotor has a magnetic body.

[0073] Feature 8: The rotor is configured to rotate around a rotating axis.

[0074] Feature 9: The rotor is configured to rotate in accordance with the changes in the magnetic field described above.

[0075] Feature 10: The above current has a d-axis component as the d-axis component and a q-axis component as the q-axis component in a d-q coordinate system with mutually orthogonal d-axis and q-axis.

[0076] Feature 11: The control circuit is configured to control the motor.

[0077] Feature 12: The control circuit is configured to allow current corresponding to the current command value to flow into the stator.

[0078] Feature 13: The control circuit is configured to control the motor by causing a current corresponding to the current command value to flow into the stator.

[0079] Feature 14: The control circuit is configured such that when the measured value of the q-axis component is contained in a region closer to the positive side of the q-axis than the intersection of the specified constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than the constant torque curve.

[0080] Feature 15: The control circuit is configured such that when the measured value of the q-axis component is contained in a region closer to the positive side of the q-axis than the intersection of the specified constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than the maximum flux efficiency curve.

[0081] Feature 16: The control circuit is configured such that when the measured value of the q-axis component is contained in a region closer to the positive side of the q-axis than the intersection of the constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve.

[0082] Feature 17: In the d-q coordinate system, the maximum flux efficiency curve is the set of points from which the maximum torque per unit flux is obtained.

[0083] According to an electric work machine having at least features 1 to 17, when switching from weak excitation control to normal vector control, the current command value is set in a direction that does not reduce torque. This allows the motor output to remain stable.

[0084] In addition to having at least one of features 1 to 17, or alternatively, a certain embodiment may also have at least one of the following features:

[0085] Feature 18: The control circuit is configured such that, when the measured value of the q-axis component is contained in a region closer to the positive side of the q-axis than the intersection point, the current command value is set in a region closer to the negative side of the q-axis than the maximum current efficiency curve.

[0086] Feature 19: The control circuit is configured such that, when the measured value of the q-axis component is contained in a region that is closer to the positive side of the q-axis than the intersection point, the current command value is set in a region that is closer to the positive side of the q-axis than the constant torque curve and closer to the negative side of the q-axis than the maximum current efficiency curve.

[0087] Feature 20: The control circuit is configured such that, when the measured value of the q-axis component is contained in a region that is closer to the positive side of the q-axis than the intersection point, the current command value is set in a region that is closer to the positive side of the q-axis than the maximum flux efficiency curve and closer to the negative side of the q-axis than the maximum current efficiency curve.

[0088] Feature 21: The control circuit is configured such that, when the measured value of the q-axis component is contained in a region that is closer to the positive side of the q-axis than the intersection point, the current command value is set in a region that is closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve, and closer to the negative side of the q-axis than the maximum current efficiency curve.

[0089] Feature 22: In the d-q coordinate system, the maximum current efficiency curve is the set of points where the maximum torque per unit current is obtained.

[0090] According to the electric work machine having at least features 1 to 22, the current command value is set to not exceed the maximum current efficiency curve. This suppresses the reduction in motor output efficiency.

[0091] In addition to having at least one of features 1 to 22, or alternatively, a certain embodiment may also have at least one of the following features:

[0092] Feature 23: The control circuit is configured to migrate between multiple modes.

[0093] Feature 24: The control circuit is configured to switch between multiple modes, including mode 1, mode 2, and mode 3.

[0094] Feature 25: The control circuit is configured to operate in one of multiple modes.

[0095] Feature 26: The control circuit is configured to switch between multiple modes, including mode 1, mode 2, and mode 3, and to operate in one of the multiple modes.

[0096] Feature 27: The control circuit is configured to set the current command value in a manner that maximizes the torque per unit current.

[0097] Feature 28: The control circuit is configured such that, in mode 1, the current command value is set in a manner that maximizes the torque per unit current.

[0098] Feature 29: The control circuit is configured to set the current command value in such a way as to generate a magnetic field in the direction of canceling the magnetic flux generated by the magnetic body.

[0099] Feature 30: The control circuit is configured such that, in the second mode, the current command value is set in such a way that a magnetic field is generated in the direction that cancels the magnetic flux generated by the magnetic body.

[0100] Feature 31: The control circuit is configured to operate via the third mode when transitioning from the second mode to the first mode.

[0101] Feature 32: The control circuit is configured to save the measured value of the current flowing through the stator as a reference measured value.

[0102] Feature 33: The control circuit is configured such that when transitioning from mode 2 to mode 3, the measured value of the current flowing through the stator is saved as a reference measured value.

[0103] Feature 34: The control circuit is configured to store the current command value as a reference command value.

[0104] Feature 35: The control circuit is configured such that when transitioning from mode 2 to mode 3, the current command value is saved as the reference command value.

[0105] Feature 36: The control circuit is configured such that when transitioning from mode 2 to mode 3, the measured value of the current flowing through the stator and the current command value are saved as the reference measured value and the reference command value, respectively.

[0106] Feature 37: The control circuit is configured to set the current command value in the third mode based on at least one of the reference measured value and the reference command value.

[0107] According to an electric work machine having at least features 1 to 37, in the third mode during the switch from a second mode equivalent to weak excitation control to a first mode equivalent to normal vector control, the current command value is set based on a reference measured value and a reference command value. This suppresses abrupt changes in the current vector. Consequently, the motor output is stabilized.

[0108] In addition to having at least one of features 1 to 37, or alternatively, a certain embodiment may also have at least one of the following features:

[0109] Feature 38: The control circuit is configured to set the current command value in the third mode based on the difference between the reference measured value and the measured current value.

[0110] Feature 39: The control circuit is configured to set the current command value in the third mode based on the reference command value.

[0111] Feature 40: The control circuit is configured to set the current command value in the third mode based on the difference between the reference measured value and the current measured value, as well as the reference command value.

[0112] According to an electric work machine having at least features 1 to 40, when switching from a second mode equivalent to weak excitation control to a first mode equivalent to normal vector control, the current command value is set based not only on the reference command value but also on the difference between the reference measured value and the measured current value. This allows the motor output to be stabilized.

[0113] In addition to having at least one of features 1 to 40, or alternatively, a certain embodiment may also have at least one of the following features:

[0114] Feature 41: The control circuit is configured to migrate from mode 2 to mode 3.

[0115] Feature 42: The control circuit is configured to migrate from mode 2 to mode 3 when the measured value of the q-axis component reaches or exceeds a specified threshold.

[0116] Based on an electric work machine having at least features 1 to 42, the operating mode can be switched according to the measured value of the q-axis component. Therefore, the motor can be controlled with the optimal operating mode corresponding to the measured value of the q-axis component.

[0117] In addition to having at least one of features 1 to 42, or alternatively, a certain embodiment may also have at least one of the following features:

[0118] Feature 43: The control circuit is configured such that the current command value is set in the region of the d-q coordinate system that is closer to the positive side of the q axis than the constant torque curve.

[0119] Feature 44: The control circuit is configured such that, in the third mode, the current command value is set in the region of the d-q coordinate system that is closer to the positive side of the q axis than the constant torque curve.

[0120] According to an electric work machine having at least features 1 to 44, when switching from a second mode equivalent to weak excitation control to a first mode equivalent to normal vector control, the current command value is set in a direction that does not reduce torque. This allows the motor output to be stabilized.

[0121] In addition to having at least one of the features 1 to 44 described above, or alternatively, a certain embodiment may also have the following features:

[0122] Feature 45: The control circuit is configured to migrate between multiple modes based on the measured values ​​of the q-axis component.

[0123] According to an electric work machine having at least characteristics 1 to 45, the motor can be controlled in the optimal operating mode corresponding to the measured value of the q-axis component.

[0124] In addition to having at least one of features 1 to 45, or alternatively, a certain embodiment may also have at least one of the following features:

[0125] Feature 46: The control circuit is configured to perform constant rotation control to maintain the motor speed at a constant level.

[0126] Feature 47: The control circuit is configured to use the d-axis component of the current command value to perform constant rotation control to maintain the motor speed at a constant level.

[0127] Based on an electric working machine having at least features 1 to 47, an appropriate current vector is set based on both the q-axis component and the d-axis component of the current command value, thereby enabling constant rotation control.

[0128] In addition to having at least one of features 1 to 47, or alternatively, a certain embodiment may also have at least one of the following features:

[0129] Feature 48: Constant rotation control includes a process that reduces the d-axis component of the current command value.

[0130] Feature 49: Constant rotation control includes a process that reduces the d-axis component of the current command value so that the current command value is set within the region of the induced voltage limiting ellipse in the d-q coordinate system.

[0131] According to an electric working machine having at least features 1 to 49, in constant rotation control, it is possible to suppress the decrease of the q-axis component of the current command value. Therefore, in constant rotation control, it is possible to suppress the decrease of torque.

[0132] In addition to having at least one of features 1 to 49, or alternatively, a certain embodiment may also have at least one of the following features:

[0133] Feature 50: The control circuit is configured to acquire the measured value of the power supply current supplied from the power source.

[0134] Feature 51: The control circuit is configured to obtain the upper limit value of the power supply current.

[0135] Feature 52: The control circuit is configured to acquire the measured value of the power supply current supplied from the power source, as well as the upper limit value of the power supply current.

[0136] Feature 53: The control circuit is configured to calculate the upper limit of the d-axis component of the current command value.

[0137] Feature 54: The control circuit is configured to calculate the upper limit of the d-axis component of the current command value based on the measured value of the power supply current.

[0138] Feature 55: The control circuit is configured to calculate the upper limit of the d-axis component of the current command value based on the upper limit of the power supply current.

[0139] Feature 56: The control circuit is configured to calculate the upper limit of the d-axis component of the current command value based on the measured value of the power supply current and the upper limit of the power supply current.

[0140] Feature 57: The control circuit is configured such that the upper limit of the d-axis component of the current command value is calculated by multiplying the difference between the measured value of the power supply current and the upper limit of the power supply current by 1 by the measured value of the d-axis component of the current flowing into the stator (i.e. the current flowing into the motor).

[0141] According to an electric work machine having at least features 1 to 57, the upper limit of the d-axis component of the current command value can be dynamically calculated based on the measured value of the power supply current in a manner that does not exceed the upper limit of the power supply current.

[0142] In addition to having at least one of features 1 to 57, or alternatively, a certain embodiment may also have the following features:

[0143] Feature 58: Configured in the third mode, the current command value is set in such a way that the motor torque is increased while the motor speed decreases.

[0144] According to an electric work machine having at least features 1 to 58, when switching from a second mode equivalent to weak excitation control to a first mode equivalent to normal vector control, it is possible to suppress a sharp decrease in motor output. This allows for a stable motor output.

[0145] Examples of electric work machines include various types of field electrical equipment used in amateur woodworking, manufacturing, gardening, construction, and other work sites and which are powered by rechargeable batteries. Specifically, this includes: power tools for stonemasonry, metalworking, and woodworking; gardening work machines; and devices for preparing the work site environment. More specifically, this includes: electric blowers, electric hammers, electric hammer drills, electric drills, electric screwdrivers, electric wrenches, electric grinders, electric circular saws, electric reciprocating saws, electric wire saws, electric cutting tools, electric chainsaws, electric planers, electric nail machines (including riveting machines), electric hedge trimmers, electric lawn trimmers, electric lawn mowers, electric lawn cleaners, electric sprayers, electric spreaders, electric dust collectors, robotic vacuum cleaners, battery-powered handcarts, battery-powered bicycles, fan vests, and heated vests.

[0146] In one embodiment, features 1 to 58 can be combined in any combination.

[0147] In one implementation, at least one of features 1 to 58 may be excluded.

[0148] One implementation may provide a control method. The control method may have at least one of the following features.

[0149] Feature 59: Controlling the motor.

[0150] Feature 60: The motor has a stator.

[0151] Feature 61: The motor has a rotor.

[0152] Feature 62: The motor has a stator and a rotor.

[0153] Feature 63: Controlling the motor.

[0154] Feature 64: Allows current corresponding to the current command value to flow into the stator.

[0155] Feature 65: The motor is controlled by causing a current corresponding to the current command value to flow into the stator.

[0156] Feature 66: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, the current command value is set in a region closer to the positive side of the q-axis than the constant torque curve.

[0157] Feature 67: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, the current command value is set in a region closer to the positive side of the q-axis than the maximum flux efficiency curve.

[0158] Feature 68: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, the current command value is set in a region closer to the positive side of the q-axis than at least one of the constant torque curve and the maximum flux efficiency curve.

[0159] Feature 69: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, the current command value is set in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve.

[0160] Feature 70: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, if the measured value of the q-axis component, which is the component of the current q-axis, is contained in a region closer to the positive side of the q-axis than the intersection of the specified constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than the constant torque curve.

[0161] Feature 71: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, if the measured value of the q-axis component, which is the component of the current, is contained in a region closer to the positive side of the q-axis than the intersection of the specified constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than the maximum flux efficiency curve.

[0162] Feature 72: In a d-q coordinate system having mutually orthogonal d-axis and q-axis, if the measured value of the q-axis component, which is the component of the current q-axis, is contained in a region closer to the positive side of the q-axis than the intersection of the specified constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than at least one of the constant torque curve and the maximum flux efficiency curve.

[0163] Feature 73: In a d-q coordinate system with mutually orthogonal d-axis and q-axis, if the measured value of the q-axis component, which is the component of the current, is contained in a region closer to the positive side of the q-axis than the intersection of the specified constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve.

[0164] According to the control method having at least features 59 to 73, it is possible to achieve the same effect as the electric work machine described above.

[0165] In addition to having at least one of features 59 to 73, or alternatively, a certain embodiment may also have at least one of the following features:

[0166] Feature 74: Migration between multiple modes.

[0167] Feature 75: Migrate between multiple modes, including Mode 1, Mode 2, and Mode 3.

[0168] Feature 76: Perform actions in one of multiple modes.

[0169] Feature 77: Set current command value.

[0170] Feature 78: Set the current command value in a way that maximizes torque per unit current.

[0171] Feature 79: In Mode 1, the current command value is set in a manner that maximizes torque per unit current.

[0172] Feature 80: Sets the current command value in such a way that a magnetic field is generated in the direction of suppressing the magnetic field generated from the magnetic body of the rotor.

[0173] Feature 81: In the second mode, the current command value is set in such a way that a magnetic field is generated in the direction of suppressing the magnetic field generated from the magnetic body of the rotor.

[0174] Feature 82: When migrating from mode 2 to mode 1, the action is performed via mode 3.

[0175] Feature 83: When migrating from mode 2 to mode 3, the measured value of the current flowing through the stator is saved as the reference measured value.

[0176] Feature 84: When migrating from mode 2 to mode 3, save the current command value as the reference command value.

[0177] Feature 85: When migrating from mode 2 to mode 3, the measured value of the current flowing through the stator and the current command value are saved as the reference measured value and the reference command value, respectively.

[0178] Feature 86: The current command value in the third mode is set based on at least one of the reference measured value and the reference command value.

[0179] Feature 87: Set the current command value in mode 3 based on both the reference measured value and the reference command value.

[0180] According to the control method having at least features 59 to 87, it is possible to achieve the same effect as the electric work machine described above.

[0181] In one embodiment, features 59 to 87 can be combined in any combination.

[0182] In one implementation, at least one of features 59 to 87 may be excluded.

[0183] [2. Specific exemplary implementation]

[0184] [2-1. Composition]

[0185] The following exemplary embodiments provide a Figure 1 The electric work machine 1 shown is equipped with a motor 6. The motor 6 has a mechanism for receiving power from a power source and being driven. As an example, the electric work machine 1 in this embodiment is in the form of an electric chainsaw. Other examples of electric work machines 1 include impact screwdrivers, electric drills, power blades, blowers, lawnmowers, hedge trimmers, etc. However, such an electric work machine 1 is only one simple example, and the present invention can be applied to all types of electric work machines.

[0186] Figure 1 Although directions such as "up," "down," "front," "back," "left," and "right" are shown, these directions are merely shown to facilitate a better understanding of the structure of the electric work machine 1 and are not intended to limit the orientation of the electric work machine 1. The electric work machine 1 can be configured in all orientations.

[0187] 2-1-1. Mechanical Structure of Electric Working Machines

[0188] like Figure 1 As shown, the electric work machine 1 has a housing 2. The motor 6, the power transmission unit 7, and the controller 13 are housed inside the housing 2.

[0189] The electric work machine 1 includes a guide rod 8. The guide rod 8 is a plate-shaped component. The guide rod 8 protrudes from the outer casing 2 toward the front of the electric work machine 1.

[0190] The electric work machine 1 is equipped with a saw chain 9. The saw chain 9 includes multiple interconnected blades. The saw chain 9 is detachably mounted to the periphery of the guide bar 8.

[0191] The power transmission unit 7 is directly or indirectly connected to the motor 6 (specifically, the rotor 19). See reference. Figure 2 The power transmission unit 7 includes a sprocket (not shown) configured for mounting the saw chain 9. The power transmission unit 7 transmits the rotational force of the motor 6 (specifically, the rotation of the rotor 19) to the saw chain 9, thereby driving the saw chain 9. When the motor 6 is driven, the saw chain 9 moves along the periphery of the guide rod 8. Thus, the saw chain 9 can work on the object being processed. Specifically, the saw chain 9 can cut workpieces such as wood, metal, and resin.

[0192] The housing 2 has a battery assembly 3 at its rear. The battery pack 15 is detachably mounted in the battery assembly 3. Figure 1 This shows the battery pack 15 assembled in the battery assembly section 3. The battery pack 15 houses a rechargeable battery 15a (see reference). Figure 2 The battery 15a includes, for example, a lithium-ion battery. While the battery pack 15 is assembled in the battery assembly section 3, the power from the battery 15a can be supplied to various parts of the electric work machine 1.

[0193] The electric work machine 1 has a front handle 4 on the upper part of the housing 2. The front handle 4 is held by the user of the electric work machine 1. The electric work machine 1 has a rear handle 5 on the rear part of the housing 2. The rear handle 5 is held by the user. The user can use the electric work machine 1, for example, by holding the front handle 4 with one hand (e.g., the left hand) and the rear handle 5 with the other hand (e.g., the right hand).

[0194] The electric work machine 1 includes a trigger 10. The trigger 10 is manually operated by the user. Specifically, the trigger 10 is pulled upwards manually. Once the trigger 10 is manually operated (i.e., pulled), the motor 6 is driven. In this embodiment, the trigger 10 is located on the rear handle 5. Thus, the user can manually operate the trigger 10 while holding the rear handle 5.

[0195] The electric work machine 1 has an unlocking stop 11 next to the trigger 10. The unlocking stop 11 is manually operated by the user (e.g., by pressing downwards). When the unlocking stop 11 is not manually operated by the user, it restricts the movement of the trigger 10. When the unlocking stop 11 is manually operated by the user, the restriction on the trigger 10 is released, and the user can manually operate the trigger 10. In this embodiment, the unlocking stop 11 is located on the rear handle 5. Thus, the user can manually operate the trigger 10 while holding the rear handle 5 and manually operating the unlocking stop 11.

[0196] The electric work machine 1 includes an operation panel 12. In this embodiment, the operation panel 12 is disposed on the upper surface of the rear end side of the housing 2. The operation panel 12 includes a mode setting switch 12a and a display 12b.

[0197] In this embodiment, the mode setting switch 12a is a momentary switch. While the mode setting switch 12a is pressed, it outputs an operation signal. While the power switch 12a is not pressed, it does not output an operation signal.

[0198] The display 12b visually informs the user of the status of the electric work machine 1. The display 12b of this embodiment includes an LED (not shown). In the following description, "on" and "off" for the display 12b mean "on" and "off" of the LED.

[0199] [2-1-2. Electrical Configuration of Electric Working Machines]

[0200] Reference Figure 2 The electrical configuration of the electric work machine 1 will now be explained. The electric work machine 1 includes the aforementioned motor 6 and controller 13.

[0201] In this embodiment, motor 6 is an internal rotor type brushless motor (specifically a three-phase brushless DC motor). In other embodiments, motor 6 can also be any other type of brushless motor (e.g., an external rotor type brushless motor).

[0202] The motor 6 includes a first coil 20a, a second coil 20b, and a third coil 20c. The first to third coils 20a, 20b, and 20c are connected in a delta configuration. However, the first to third coils 20a, 20b, and 20c can also be connected in a different configuration than the delta configuration. For example, the first to third coils 20a, 20b, and 20c can be connected in a star configuration.

[0203] The motor 6 includes a stator 17, which is configured to generate a magnetic field through the flow of current. Specifically, the stator 17 has three coils 20a, 20b, and 20c. The stator 17 has multiple teeth (not shown), and the three coils 20a, 20b, and 20c are wound around these teeth. The stator 17 generates a magnetic field by the flow of current into the three coils 20a, 20b, and 20c.

[0204] The motor 6 includes a rotor 19. The rotor 19 is configured to pass through the stator 17 and is rotatably supported by bearings (not shown). The rotor 19 has one or more magnetic elements. These magnetic elements may include, for example, permanent magnets. That is, the rotor 19 has multiple magnetic poles along the direction of rotation. Specifically, in the rotor 19, N poles and S poles are alternately arranged along the direction of rotation. Figure 2 The rotor 19, with "N" schematically representing the N pole and "S" schematically representing the S pole, rotates around the rotation axis in response to the changes in the magnetic field generated by the stator 17.

[0205] Figure 2For simplicity, the motor 6 is shown as a brushless motor with a 2-pole, 3-slot (i.e., 3-tooth) configuration. However, the motor 6 of this invention actually has 4 or more magnetic poles and 6 or more slots (i.e., 6 or more teeth). Of course, the motor 6 can also actually be in a 2-pole, 3-slot configuration.

[0206] The motor 6 includes a first terminal 6a, a second terminal 6b, and a third terminal 6c. The first terminal 6a is connected to the first end of the first coil 20a and the first end of the third coil 20c. The second terminal 6b is connected to the second end of the first coil 20a and the first end of the second coil 20b. The third terminal 6c is connected to the second end of the second coil 20b and the second end of the third coil 20c.

[0207] The electric work machine 1 is equipped with a position signal output circuit 21. The position signal output circuit 21 is located next to the motor 6 (specifically next to the rotor 19).

[0208] The position signal output circuit 21 includes a first rotation sensor 21a, a second rotation sensor 21b, and a third rotation sensor 21c. The first to third rotation sensors 21a to 21c are each configured to detect the magnetic flux density around the rotor 19 (i.e., the magnetic flux density around the magnetic body of the rotor 19). In this embodiment, the first to third rotation sensors 21a to 21c are Hall sensors, but are not limited to Hall sensors.

[0209] The first to third rotation sensors 21a to 21c are configured to move a predetermined distance away from the rotor 19 in the direction along the rotation axis of the rotor 19. The first to third rotation sensors 21a to 21c are configured to be electrically separated from each other by 120 degrees along the rotation direction of the rotor 19.

[0210] The first rotation sensor 21a outputs the first Hall signal Hu, the second rotation sensor 21b outputs the second Hall signal Hv, and the third rotation sensor 21c outputs the third Hall signal Hw. The first to third Hall signals Hv, Hu, and Hw are digital signals (i.e., binary signals). Whenever the rotor 19 rotates 180 degrees, the logic values ​​of the first to third Hall signals Hu, Hv, and Hw are reversed. The phases of the first to third Hall signals Hu, Hv, and Hw are offset by 120 degrees.

[0211] The electric work machine 1 includes a power line Lp. The power line Lp extends from the positive terminal of the battery pack 15, which is mounted in the battery assembly 3, toward the controller 13. The electric work machine 1 also includes a grounding wire Ln. The grounding wire Ln extends from the negative terminal of the battery pack 15, which is mounted in the battery assembly 3, toward the controller 13. The battery pack 15 applies a voltage (hereinafter referred to as "battery voltage") from the battery 15a between the power line Lp and the grounding wire Ln.

[0212] The controller 13 includes a power supply circuit 32. The power supply circuit 32 is connected to the power line Lp and receives the battery voltage Vbat via the power line Lp. The power supply circuit 32 generates a DC voltage based on the battery voltage. Hereinafter, the DC voltage will be referred to as the power supply voltage Vc.

[0213] The controller 13 includes a control circuit 30. The control circuit 30 operates upon receiving a power supply voltage Vc. The control circuit 30 is a microcomputer comprising a processor 30a and a memory 30b. The memory 30b is in the form of a semiconductor memory. The memory 30b includes ROM (Read Only Memory), RAM (Random Access Memory), and rewritable non-volatile memory. Examples of non-volatile memory include EEPROM (Electrically Erasable and Programmable Read Only Memory), flash memory, ReRAM (Resistive RAM), and FeRAM (Ferroelectric RAM). The various functions of the control circuit 30 are implemented by the processor 30a executing a computer program stored in the memory 30b. The processor 30a executes the program to perform the corresponding method.

[0214] In other embodiments, the control circuit 30 may include an additional microcontroller. Furthermore, in other embodiments, some or all of the functions performed by the processor 30a may be implemented using one or more electronic devices (e.g., integrated circuits). Furthermore, in other embodiments, the control circuit 30 may also be a logic circuit (or hardwired logic connection) including two or more electronic devices. Furthermore, in other embodiments, the control circuit 30 may also include an ASIC (Application Specific Integrated Circuit) and / or an ASSP (Application Specific Standard Product). Furthermore, in other embodiments, the control circuit 30 may also include a programmable logic device capable of constructing reconfigurable logic circuits. Examples of programmable logic devices include FPGAs (Field Programmable Gate Arrays).

[0215] The controller 13 includes a drive circuit 31. The drive circuit 31 is electrically connected to a power supply line Lp and a ground line Ln, and receives battery voltage via the power supply line Lp and the ground line Ln. The drive circuit 31 is electrically connected to the motor 6 via a first lead 26, a second lead 27, and a third lead 28. Specifically, the first lead 26 is connected to the first terminal 6a of the motor 6. The second lead 27 is connected to the second terminal 6b of the motor 6. The third lead 28 is connected to the third terminal 6c of the motor 6.

[0216] The drive circuit 31 generates a three-phase voltage (i.e., generates three-phase power) based on the battery voltage. The drive circuit 31 supplies the generated three-phase voltage to the motor 6 via leads 1 to 3, 26 to 28. In the following description, the current flowing through lead 1, 26, is referred to as the U-phase motor current, the current flowing through lead 27, 27, is referred to as the V-phase motor current, and the current flowing through lead 3, 28, is referred to as the W-phase motor current.

[0217] The driving circuit 31 in this embodiment is a three-phase full-bridge circuit, but it is not limited to a three-phase full-bridge circuit.

[0218] The drive circuit 31 has first to third current paths Lp1 to Lp3, which serve as the so-called upper bridge arm. The first to third current paths Lp1 to Lp3 electrically connect the power line Lp to the first to third terminals 6a, 6b, and 6c of the motor 6, respectively.

[0219] The drive circuit 31 has 4th to 6th current paths Lp4 to Lp6, which serve as the so-called lower bridge arm. The 4th to 6th current paths Lp4 to Lp6 electrically connect the ground wire Ln to the 1st to 3rd terminals 6a, 6b, and 6cc of the motor 6, respectively.

[0220] The drive circuit 31 includes: a first switch Q1 on the first current path Lp1, a second switch Q2 on the second current path Lp2, a third switch Q3 on the third current path Lp3, a fourth switch Q4 on the fourth current path Lp4, a fifth switch Q5 on the fifth current path Lp5, and a sixth switch Q6 on the sixth current path Lp6.

[0221] Switches Q1 to Q3 (numbers 1-3) function as high-side switches. Switches Q4 to Q6 (numbers 4-6) function as low-side switches. Current paths Lp1 to Lp3 (numbers 1-3) are either turned on or off by switches Q1 to Q3. Current paths Lp4 to Lp6 (numbers 4-6) are either turned on or off by switches Q4 to Q6.

[0222] Switches Q1 to Q6 are semiconductor switches. In this embodiment, switches Q1 to Q6 are n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs). However, switches Q1 to Q6 can also be other types of semiconductor switches, such as bipolar transistors, insulated-gate bipolar transistors (IGBTs), etc.

[0223] Switch Q1 receives a first drive signal UH from control circuit 30 and switches on or off according to UH. Switch Q2 receives a second drive signal VH from control circuit 30 and switches on or off according to VH. Switch Q3 receives a third drive signal WH from control circuit 30 and switches on or off according to WH. Switch Q4 receives a fourth drive signal UL from control circuit 30 and switches on or off according to UL. Switch Q5 receives a fifth drive signal VL from control circuit 30 and switches on or off according to VL. Switch Q6 receives a sixth drive signal WL from control circuit 30 and switches on or off according to WL. In this embodiment, the first to sixth drive signals UH, VH, WH, UL, VL, and WL can be PWM (Pulse Width Modulation) signals.

[0224] When motor 6 is driven, in principle, any one high-side switch and any one low-side switch are turned on. Accordingly, current (hereinafter referred to as "bus current") flows from the positive terminal of battery pack 15 through the high-side switch, motor 6, and the low-side switch to the negative terminal of battery pack 15, thereby causing motor 6 to rotate.

[0225] The drive circuit 31 includes a first current detection circuit 36 ​​on the first lead 26. The first current detection circuit 36 ​​detects the current flowing through the first lead 26 (hereinafter referred to as the "U-phase current"). Specifically, the first current detection circuit 36 ​​outputs a U-phase current detection signal Siu corresponding to the magnitude of the U-phase current. The U-phase current detection signal Siu is input to the control circuit 30.

[0226] The drive circuit 31 includes a second current detection circuit 37 on the second lead 27. The second current detection circuit 37 detects the current flowing through the second lead 27 (hereinafter referred to as the "V-phase current"). Specifically, the second current detection circuit 37 outputs a V-phase current detection signal Siv corresponding to the magnitude of the V-phase current. The V-phase current detection signal Siv is input to the control circuit 30.

[0227] The drive circuit 31 includes a third current detection circuit 38 on the third lead 28. The third current detection circuit 38 detects the current flowing through the third lead 28 (hereinafter referred to as the "W-phase current"). Specifically, the third current detection circuit 38 outputs a W-phase current detection signal Siw corresponding to the magnitude of the W-phase current. The W-phase current detection signal Siw is input to the control circuit 30.

[0228] The controller 13 includes a bus current detection circuit 33. The bus current detection circuit 33 is located on the current path through which the bus current flows. In this embodiment, the bus current detection circuit 33 is located on the ground line Ln within the controller 13, and more specifically, on the current path between the drive circuit 31 and the ground. The bus current detection circuit 33 detects the bus current. Specifically, the bus current detection circuit 33 outputs a bus current detection signal Sib corresponding to the magnitude of the bus current. The bus current detection signal Sib is input to the control circuit 30.

[0229] The controller 13 includes a first temperature detection circuit 39. The first temperature detection circuit 39 is located within or next to the drive circuit 31. The first temperature detection circuit 39 includes a first temperature sensor (not shown). The first temperature sensor is, for example, a thermistor. The first temperature sensor outputs a first temperature detection signal Std corresponding to the temperature around the sensor. The first temperature detection signal Std is input to the control circuit 30. The first temperature detection signal Std directly or indirectly represents the temperature of the first to sixth switches Q1 to Q6 (in other words, the temperature of the drive circuit 31). That is, the first temperature detection circuit 39 is provided for detecting the temperature of the drive circuit 31.

[0230] The electric work machine 1 includes a second temperature detection circuit 23. The second temperature detection circuit 23 is located inside or beside the motor 6. The second temperature detection circuit 23 includes a second temperature sensor (not shown). The second temperature sensor is, for example, a thermistor. The second temperature sensor outputs a second temperature detection signal Stm corresponding to the temperature around the sensor. The second temperature detection signal Stm is input to the control circuit 30. The second temperature detection signal Stm directly or indirectly represents the temperature of the motor 6. That is, the second temperature detection circuit 23 is provided for detecting the temperature of the motor 6.

[0231] The electric work machine 1 includes a trigger detection circuit 22. The trigger detection circuit 22 is mechanically connected to the trigger 10 and outputs a first trigger signal TR1 and a second trigger signal TR2 corresponding to the state of the trigger 10. The first trigger signal TR1 is a binary signal indicating whether the trigger 10 is manually operated. For example, when the trigger 10 is not manually operated, the first trigger signal TR1 is a low-level signal; when the trigger 10 is manually operated, the first trigger signal TR1 is a high-level signal. The second trigger signal TR2 is an analog signal corresponding to the amount of movement (in other words, the pulling amount) of the trigger 10 from its initial position during the period when the trigger 10 is manually operated.

[0232] The first and second trigger signals TR1 and TR2 are input to the control circuit 30. Based on the first and second trigger signals TR1 and TR2, the control circuit 30 can obtain whether the trigger 10 is turned on (i.e., manually operated) and the amount of movement of the trigger 10 when the trigger 10 is manually operated.

[0233] The aforementioned mode setting switch 12a and display 12b are electrically connected to the control circuit 30. The control circuit 30 receives an operation signal from the mode setting switch 12a. Based on the presence or absence of the operation signal, the control circuit 30 can identify whether the mode setting switch 12a has been pressed.

[0234] In this embodiment, even if the battery pack 15 is installed in the battery assembly section 3, the power supply voltage Vc is not immediately generated. After the battery pack 15 is installed, the power supply voltage Vc is generated corresponding to the mode setting switch 12a being pressed and held, thereby activating the control circuit 30. A "press and hold" means, for example, that the mode setting switch 12a has been continuously pressed for a first predetermined time (e.g., 2 to 3 seconds) or more.

[0235] The control circuit 30 sets the operating mode of the electric work machine 1 to either a high-speed mode or a high-torque mode. Specifically, when the control circuit 30 starts upon receiving the power supply voltage Vc, it sets the operating mode to high-speed mode. Thereafter, each time the mode setting switch 12a is briefly pressed, the operating mode of the electric work machine alternately switches between high-torque mode → high-speed mode → high-torque mode… A brief press means, for example, pressing the mode setting switch 12a and then releasing the press operation before a second predetermined time has elapsed. The second predetermined time is less than the first predetermined time.

[0236] The control circuit 30 controls the display 12b (specifically, an LED in this embodiment) according to the state of the electric work machine 1. For example, the control circuit 30 illuminates the display 12b in a first state when the operating mode is set to high-speed mode, and in a second state when the operating mode is set to high-torque mode. The first state can be, for example, illuminating the LED with a first color (e.g., green). The second state can be, for example, illuminating the LED with a second color (e.g., yellow).

[0237] Additionally, the high-speed mode prioritizes rotating motor 6 at a higher speed, while the high-torque mode prioritizes rotating motor 6 with higher torque. The high-speed and high-torque modes will be described in detail later.

[0238] The control circuit 30 receives the first to third Hall signals Hu, Hv, and Hw from the position signal output circuit 21. As mentioned earlier, the phases of the first to third Hall signals Hu, Hv, and Hw are offset from each other by an electrical angle of 120 degrees. Therefore, whenever the rotor 19 rotates by an electrical angle of 60 degrees, the logic value of any one of the first to third Hall signals Hu, Hv, and Hw changes. Based on the change in logic value every 60 degrees, the control circuit 30 detects the rotational position (in other words, the rotation angle) and rotational speed of the motor 6.

[0239] The control circuit 30 also receives the aforementioned first temperature detection signal Std and second temperature detection signal Stm.

[0240] The control circuit 30 also receives the aforementioned U-phase current detection signal Siu, V-phase current detection signal Siv, and W-phase current detection signal Siw.

[0241] The control circuit 30 controls the rotation of the motor 6 based on various input signals, as described later.

[0242] [2-1-3. Functional Composition of Control Circuit]

[0243] like Figure 3As shown, the control circuit 30 has multiple functions. Specifically, the control circuit 30 includes: a speed calculation unit 41, a current conversion unit 42, an instruction unit 43, a speed control unit 44, a weak excitation control unit 45, a limit value calculation unit 46, a current control unit 47, and a voltage conversion unit 48. In this embodiment, these functions are integrated into the control circuit 30 via software. That is, these functions are implemented by the processor 30a executing the corresponding program. The specific processing of these functions will be described later.

[0244] In other embodiments, at least one of the functions of the speed calculation unit 41, current conversion unit 42, command unit 43, speed control unit 44, weak excitation control unit 45, limit value calculation unit 46, current control unit 47, and voltage conversion unit 48 may be integrated into the control circuit 30 by hardware (e.g., dedicated electronic circuitry) rather than by software. Alternatively, in other embodiments, at least one of the functions of the speed calculation unit 41, current conversion unit 42, command unit 43, speed control unit 44, weak excitation control unit 45, limit value calculation unit 46, current control unit 47, and voltage conversion unit 48 may be removed.

[0245] Hall signals Hu, Hv, and Hw, from the first to the third position signal output circuit 21 (see reference) Figure 2 The calculated rotation angle θ and the measured speed ω_m of the rotor 19 are input to the speed calculation unit 41. The speed calculation unit 41 calculates the rotation angle θ and the measured speed ω_m of the rotor 19 based on the first to third Hall signals Hu, Hv, and Hw. The measured speed ω_m is the measured value of the rotational speed of the rotor 19. The unit of the measured speed ω_m is, for example, rpm (revolutions per minute). There is no particular limitation on the method for calculating the rotation angle θ and the measured speed ω_m based on the first to third Hall signals Hu, Hv, and Hw; known methods can be used. The speed calculation unit 41 outputs the calculated rotation angle θ to the current conversion unit 42 and the voltage conversion unit 48, and outputs the calculated measured speed ω_m to the speed control unit 44 and the weak excitation control unit 45.

[0246] The detected values ​​of the three-phase currents (U, V, and W phases) are input to the current conversion unit 42. The detected values ​​of the three-phase currents input to the current conversion unit 42 are: the U, V, and W phase current detection signals Siu, Siv, and Siw from the first to third current detection circuits 36, 37, and 38. The U, V, and W phase current detection signals Siu, Siv, and Siw represent the detected values ​​of the U, V, and W phase currents detected by the first to third current detection circuits 36, 37, and 38, that is, the measured values ​​of the U, V, and W phase currents.

[0247] The current conversion unit 42 converts the detected values ​​of the three-phase currents (U, V, W phases) into two-phase currents Id and Iq in the d-q coordinate system, namely the d-axis current Id and the q-axis current Iq. The current conversion unit 42 can, for example, convert the detected values ​​of the three-phase currents into two-phase currents Id and Iq using Clarke transformation and Park transformation.

[0248] The d-q coordinate system is a known rotating coordinate system with mutually orthogonal d-axis and q-axis. The d-axis represents the direction of magnetic flux of the magnetic body of the rotor 19 within the motor 6. The negative direction of the d-axis is the direction that counteracts the magnetic flux generated by the magnetic body of the rotor 19. The q-axis represents the direction in which torque is generated in the rotor 19. The positive direction of the q-axis is not particularly defined. For example, the direction of the torque applied to the rotor 19 to accelerate the motor 6 can be the positive direction of the q-axis, and the direction opposite to this torque can be the negative direction of the q-axis. The d-axis current Id is the d-axis component of the current vector I. The q-axis current Iq is the q-axis component of the current vector I.

[0249] Specifically, the current conversion unit 42 calculates the measured d-axis current value Id_m as the d-axis current Id based on the U, V, and W phase current detection signals Siu, Siv, and Siw, and calculates the measured q-axis current value Iq_m as the q-axis current Iq. The current conversion unit 42 outputs the calculated measured d-axis current value Id_m to the limit value calculation unit 46 and the current control unit 47, and outputs the calculated measured q-axis current value Iq_m to the weak excitation control unit 45 and the current control unit 47.

[0250] The first trigger signal TR1 and the second trigger signal TR2 of trigger 10 are input to the speed command unit 43. The speed command unit 43 calculates the speed command value ω_r based on the first trigger signal TR1 and the second trigger signal TR2. The speed command value ω_r is the command value for the rotational speed of rotor 19. When the first trigger signal TR1 indicates that trigger 10 is not manually operated, the speed command unit 43 calculates the speed command value ω_r as 0. When the first trigger signal TR1 indicates that trigger 10 is manually operated, the speed command unit 43 calculates the speed command value ω_r in such a way that the larger the pull amount of trigger 10 indicated by the second trigger signal TR2, the larger the value. The speed command unit 43 outputs the calculated speed command value ω_r to the speed control unit 44 and the weak excitation control unit 45.

[0251] The speed command value ω_r and the measured speed value ω_m are input to the speed control unit 44. Based on the speed command value ω_r and the measured speed value ω_m, the speed control unit 44 calculates the q-axis current command value Iq_r. For example, the speed control unit 44 calculates the q-axis current command value Iq_r using PI (Proportional-Integral) control. The speed control unit 44 outputs the calculated q-axis current command value Iq_r to the weak excitation control unit 45.

[0252] The q-axis current command value Iq_r, the measured q-axis current value Iq_m, the speed command value ω_r, the measured speed value ω_m, and the duty cycle Duty are input to the weak excitation control unit 45. Based on these values, the weak excitation control unit 45 calculates the q-axis current command value Iq_r and the d-axis current command value Id_r. The specific processing performed by the weak excitation control unit 45 will be described later. The weak excitation control unit 45 outputs the calculated d-axis current command value Id_r to the first limiter L1 and the q-axis current command value Iq_r to the current control unit 47.

[0253] The bus current detection signal Sib, the upper limit value of the bus current Ib_limit, and the measured value of the d-axis current Id_m are input to the limit value calculation unit 46. The limit value calculation unit 46 calculates the d-axis current limit value Id_limit based on the bus current detection signal Sib, the upper limit value of the bus current Ib_limit, and the measured value of the d-axis current Id_m. The upper limit value of the bus current Ib_limit is the upper limit of the bus current. The upper limit value of the bus current Ib_limit can be obtained from the battery pack 15. The upper limit value of the bus current Ib_limit changes dynamically according to the measured speed ω_m of the rotor 19. The d-axis current limit value Id_limit is: the upper limit and / or lower limit of the d-axis current Id that can flow into the control circuit 30. The specific processing performed by the limit value calculation unit 46 will be described later. The limit value calculation unit 46 outputs the calculated d-axis current limit value Id_limit to the first limiter L1.

[0254] The d-axis current command value Id_r and the d-axis current limit value Id_limit are input to the first limiter L1. Based on the d-axis current command value Id_r and the d-axis current limit value Id_limit, the first limiter L1 calculates the d-axis current command value Id_r, which is limited by an upper limit of "0" and a lower limit of the d-axis current limit value Id_limit. The first limiter L1 outputs the calculated d-axis current command value Id_r to the current control unit 47.

[0255] The q-axis current command value Iq_r, the measured q-axis current value Iq_m, the d-axis current command value Id_r, and the measured d-axis current value Id_m are input to the current control unit 47. Based on the q-axis current command value Iq_r, the measured q-axis current value Iq_m, the d-axis current command value Id_r, and the measured d-axis current value Id_m, the current control unit 47 calculates the q-axis voltage command value Vq_r, the d-axis voltage command value Vd_r, and the duty cycle Duty. The calculated duty cycle Duty is the duty cycle Duty of the 1st to 6th drive signals UH, VH, WH, UL, VL, and WL. The current control unit 47 calculates the q-axis voltage command value Vq_r, the d-axis voltage command value Vd_r, and the duty cycle Duty, for example, through PI control. The current control unit 47 outputs the calculated q-axis voltage command value Vq_r and d-axis voltage command value Vd_r to the voltage conversion unit 48, and outputs the calculated duty cycle Duty to the weak excitation control unit 45.

[0256] The q-axis voltage command value Vq_r, the d-axis voltage command value Vd_r, and the rotation angle θ are input to the voltage conversion unit 48. The voltage conversion unit 48 calculates the three-phase voltage command values ​​based on the q-axis voltage command value Vq_r, the d-axis voltage command value Vd_r, and the rotation angle θ. For example, the voltage conversion unit 48 converts the two-phase voltages of the q-axis voltage command value Vq_r and the d-axis voltage command value Vd_r into three-phase voltage command values ​​through inverse Clarke transformation and inverse Park transformation. The voltage conversion unit 48 outputs the calculated three-phase voltage command values ​​as the first to sixth drive signals UH, VH, WH, UL, VL, and WL to the drive circuit 31 (see reference). Figure 2 The three-phase voltage is supplied to the motor 6 through the drive circuit 31.

[0257] [2-1-4. Structure of the Limit Value Calculation Unit]

[0258] use Figure 4 The following describes the specific processing performed by the limit value calculation unit 46. First, the limit value calculation unit 46 acquires the bus current detection signal Sib and the bus current upper limit value Ib_limit, and calculates the difference between the bus current value Ib, which is the current value represented by the bus current detection signal Sib, and the bus current upper limit value Ib_limit. The calculated current difference is attenuated by a gain K. For example, the gain K attenuates the input value to a factor of 0.001.

[0259] Next, the limit calculation unit 46 adds the current difference attenuated by the gain K to the constant value "1" and inputs it to the second limiter L2. Constants C1 and C2 are input to the upper and lower limits of the second limiter L2, respectively. Constants C1 and C2 are set to satisfy (C1 + C2) / 2 = 1. For example, C1 = 2 and C2 = 0.

[0260] Next, the limit calculation unit 46 uses the multiplier MULT to multiply the output value of the second limiter L2 and the measured d-axis current value Id_m, and inputs the result to the low-pass filter LPF to calculate the d-axis current limit value Id_limit as the output. The cutoff frequency of the low-pass filter LPF is set to, for example, 100Hz.

[0261] Thus, the limit calculation unit 46 calculates the d-axis current limit value Id_limit based on the bus current detection signal Sib, the upper limit value of the bus current Ib_limit, and the measured value of the d-axis current Id_m.

[0262] [2-2. Treatment]

[0263] [2-2-1. Interruption Handling]

[0264] use Figures 5-11 This describes a series of processes performed by the processor 30a of the control circuit 30.

[0265] The control circuit 30 repeats this process at a constant cycle. Figure 5 The interrupt handling is shown. The constant period is, for example, 20kHz or 10kHz.

[0266] First, in S10, the control circuit 30 calculates the rotation angle θ and the measured speed ω_m of the rotor 19 using the speed calculation unit 41. The rotation angle θ and the measured speed ω_m are calculated based on the first to third Hall signals Hu, Hv, and Hw.

[0267] Next, in S20, the control circuit 30 converts the three-phase currents represented by the U, V, and W phase current detection signals Siu, Siv, and Siw into two-phase currents Id and Iq, namely the d-axis current Id and the q-axis current Iq, through the current conversion unit 42.

[0268] Next, in S30, the control circuit 30 calculates the speed command value ω_r using the instruction unit 43. The speed command value ω_r is calculated based on the first trigger signal TR1 and the second trigger signal TR2.

[0269] Next, in S40, the control circuit 30 calculates the q-axis current command value Iq_r using the speed control unit 44. The q-axis current command value Iq_r is calculated based on the speed command value ω_r.

[0270] Next, in S50, the control circuit 30 calculates the q-axis current command value Iq_r and the d-axis current command value Id_r using the weak excitation control unit 45. The q-axis current command value Iq_r and the d-axis current command value Id_r are calculated based on the q-axis current command value Iq_r, the measured q-axis current value Iq_m, the speed command value ω_r, the measured speed value ω_m, and the duty cycle (Duty). The specific processing in S50 will be described later.

[0271] Next, in S60, the control circuit 30 calculates the d-axis current limit value Id_limit using the limit value calculation unit 46. The d-axis current limit value Id_limit is calculated based on the bus current detection signal Sib, the upper limit value of the bus current Ib_limit, and the measured value of the d-axis current Id_m.

[0272] Next, in S70, the control circuit 30 calculates the q-axis voltage command value Vq_r, the d-axis voltage command value Vd_r, and the duty cycle Duty through the current control unit 47. The q-axis voltage command value Vq_r, the d-axis voltage command value Vd_r, and the duty cycle Duty are calculated based on the q-axis current command value Iq_r, the measured q-axis current value Iq_m, the d-axis current command value Id_r, and the measured d-axis current value Id_m.

[0273] Next, in S80, the control circuit 30 converts the two-phase voltages, namely the q-axis voltage command value Vq_r and the d-axis voltage command value Vd_r, into three-phase voltage command values ​​via the voltage conversion unit 48. The control circuit 30 outputs the converted three-phase voltage command values ​​as the first to sixth drive signals UH, VH, WH, UL, VL, and WL to the drive circuit 31, and supplies the three-phase voltage to the motor 6 through the drive circuit 31.

[0274] After this, control circuit 30 ends. Figure 5 The interrupt handling is shown.

[0275] In this way, the control circuit 30 controls the d-axis current Id and q-axis current Iq of the current vector I flowing into the motor 6 based on the measured values ​​of the three-phase current flowing into the motor 6, the first to third Hall signals Hu, Hv, Hw representing the magnetic flux density around the rotor 19, the first trigger signal TR1 and the second trigger signal TR2 corresponding to the state of the trigger 10, and the bus current detection signal Sib, thereby controlling the three-phase voltage supplied to the motor 6.

[0276] [2-2-2. Operating Mode of Control Circuit]

[0277] like Figure 6As shown, the control circuit 30 has MTPA mode M1, weak excitation mode M2, mid-migration mode M3, and regenerative mode M4 as operating modes. The control circuit 30 operates in one of these multiple modes. However, the multiple modes are not limited to these, and may include other operating modes. The control circuit 30 may also operate without regenerative mode M4.

[0278] MTPA mode M1 is an operating mode in which the motor 6 is controlled by so-called MTPA (Maximum Torque Per Ampere) control. That is, in MTPA mode M1, the control circuit 30 sets the d-axis current command value Id_r in a manner that maximizes the torque of the motor 6 per unit current.

[0279] The weak excitation mode M2 ​​is an operating mode in which the motor 6 is controlled by so-called weak excitation control. That is, the weak excitation mode M2 ​​is an operating mode in which the magnetic field of the stator 17 is generated in a way that suppresses the magnetic field generated by the magnetic body of the rotor 19, thereby controlling the d-axis current command value Id_r.

[0280] The mid-transition mode M3 is the operating mode used when transitioning from the weak excitation mode M2 ​​to the MTPA mode M1. That is, the control circuit 30 operates via the mid-transition mode M3 when transitioning from the weak excitation mode M2 ​​to the MTPA mode M1.

[0281] Regeneration mode M4 is an operating mode used to reduce the rotational speed or torque of motor 6. For example, when the user of the electric work machine 1 manually operates it from the state of pulling the trigger 10 to the state of not pulling the trigger 10, the control circuit 30 operates in regeneration mode M4.

[0282] Control circuit 30 as described later Figures 7-11 The process shown transitions between MTPA mode M1, weak excitation mode M2, mid-migration mode M3, and regenerative mode M4. The initial state of control circuit 30 is MTPA mode M1.

[0283] The control circuit 30, which operates in MTPA mode M1, can migrate to weak excitation mode M2 ​​or regenerative mode M4.

[0284] The control circuit 30, which operates in the weak excitation mode M2, can migrate to the mid-migration mode M3 or the regeneration mode M4.

[0285] The control circuit 30, which operates in the mid-migration mode M3, can migrate to the MTPA mode M1, the weak excitation mode M2, or the regenerative mode M4.

[0286] The control circuit 30, which operates in regeneration mode M4, can migrate to MTPA mode M1.

[0287] [2-2-3. Weak excitation control processing]

[0288] Control circuit 30 in Figure 5 Execution in S50 Figure 7 The weak excitation control process is shown. In the weak excitation control process, the control circuit 30 performs the processing corresponding to the operating mode.

[0289] First, in S100, the control circuit 30 determines whether the q-axis current command value Iq_r < 0.

[0290] If the control circuit 30 determines that the q-axis current command value Iq_r < 0 (S100: YES), it switches to S110 and transitions to regenerative mode M4. Afterward, it switches to S120.

[0291] If the control circuit 30 determines that the q-axis current command value Iq_r is not 0 (S100: NO), it will proceed to S120.

[0292] Next, in S120, the control circuit 30 determines what the current operating mode is.

[0293] When the operating mode is MTPA mode M1, the control circuit 30 switches to S130 to execute. Figure 8 The MTPA process is shown.

[0294] When the operating mode is weak excitation mode M2, the control circuit 30 switches to S140 to execute. Figure 9 The weak excitation treatment shown.

[0295] When the operation mode is mid-transition mode M3, the control circuit 30 switches to S150 and executes... Figure 10 The migration process shown is handled midway.

[0296] When the operating mode is regenerative mode M4, the control circuit 30 switches to S160 to execute... Figure 11 The regeneration process is shown.

[0297] The details of MTPA processing, weak excitation processing, mid-migration processing, and regeneration processing will be described later. After this, control circuit 30 ends. Figure 7 The weak excitation control process is shown.

[0298] In this way, the control circuit 30 performs the processing corresponding to the operating mode.

[0299] [2-2-4. MTPA Processing]

[0300] use Figure 8 The flowchart below illustrates the MTPA process performed by the control circuit 30. The MTPA process refers to the processing performed by the control circuit 30 in MTPA mode M1.

[0301] First, in S200, the control circuit 30 calculates the d-axis current value, i.e., the MTPA current value Id_mtpa, during MTPA control. In the following formula (1), the q-axis current command value Iq_r can be substituted into the q-axis current Iq to calculate the MTPA current value Id_mtpa.

[0302]

Mathematical Formula 1

[0303]

[0304] In equation (1), Ψa is the d-axis component of the magnetic flux vector of the magnetic body in rotor 19. Lq is the q-axis inductance. Ld is the d-axis inductance. The unit of Ψa is, for example, Weber. The units of Lq and Ld are, for example, Henry.

[0305] A table can be pre-made to calculate the MTPA current value Id_mtpa corresponding to the q-axis current Iq. The control circuit 30 can calculate the MTPA current value Id_mtpa by referring to this table and based on the q-axis current command value Iq_r.

[0306] Next, in S210, the control circuit 30 sets the MTPA current value Id_mtpa to the d-axis current command value Id_r.

[0307] Next, in S220, the control circuit 30 determines whether the duty cycle Duty is greater than or equal to the first duty cycle threshold TH_D1.

[0308] The first duty cycle threshold TH_D1 is a threshold used to determine whether the output voltage of the drive circuit 31 is saturated. For example, the first duty cycle threshold TH_D1 is 98%.

[0309] If the duty cycle (Duty) is not greater than or equal to the first duty cycle threshold (TH_D1) (S220: NO), control circuit 30 terminates. Figure 8 The MTPA process is shown.

[0310] On the other hand, when the duty cycle Duty ≥ the first duty threshold TH_D1 (S220: YES), the control circuit 30 switches to S230 to determine whether the measured value of the q-axis current Iq_m is < the first current threshold TH_I1.

[0311] The first current threshold TH_I1 is used to determine whether to migrate to the weak excitation mode M2. For example, the first current threshold TH_I1 is 20 amperes.

[0312] If the measured q-axis current value Iq_m is not less than the first current threshold TH_I1 (S230: NO), then control circuit 30 terminates. Figure 8 The MTPA process is shown.

[0313] On the other hand, if the measured value of the q-axis current Iq_m is less than the first current threshold TH_I1 (S230: YES), the control circuit 30 switches to S240 to determine whether the speed command value ω_r is greater than the speed target value ω_t × constant C3.

[0314] The target speed value ω_t is a threshold used to determine whether motor 6 is in an acceleration state. When the user initially pulls trigger 10, motor 6 is in an acceleration state. During the acceleration period, control circuit 30 operates in MTPA mode M1. During the acceleration period, once a weak excitation process is performed, motor 6 does not output torque and cannot accelerate. Therefore, during periods when the speed command value ω_r exceeds the specified target value, control circuit 30 controls the motor without transitioning to weak excitation mode M2. The target speed value ω_t is, for example, approximately 35000 rpm.

[0315] A constant C3 is preset. The constant C3 can be set to a value greater than or less than 1. Preferably, the constant C3 is set to a value in the range of 0.10 to 0.99. In this embodiment, as an example, the constant C3 is set to 0.8.

[0316] If the speed command value ω_r is not greater than the speed target value ω_t × constant C3 (S240: NO), control circuit 30 terminates. Figure 8 The MTPA process is shown.

[0317] On the other hand, if the speed command value ω_r > the speed target value ω_t × constant C3 (S240: YES), the control circuit 30 switches to S250, transitioning to the weak excitation mode M2. After this, the process ends. Figure 8 The MTPA process is shown.

[0318] Thus, in MTPA mode M1, control circuit 30 sets the d-axis current command value Id_r to the MTPA current value Id_mtpa. Furthermore, based on specified conditions (i.e., conditions S220, S230, and S240), control circuit 30 transitions to weak excitation mode M2.

[0319] [2-2-5. Weak excitation treatment]

[0320] use Figure 9The flowchart below illustrates the weak excitation process performed by the control circuit 30. The weak excitation process refers to the processing performed by the control circuit 30 in the weak excitation mode M2.

[0321] First, in S300, the control circuit 30 adds the gain × (measured q-axis current value Iq_m - commanded q-axis current value Iq_r) to the commanded d-axis current value Id_r. The gain at this point is, for example, 0.0008.

[0322] Alternatively, control circuit 30 can convert the value of gain × (measured speed value ω_m - speed command value ω_r) into a current value and add it to the d-axis current command value Id_r. In this case, the gain is, for example, 0.00015.

[0323] Next, in S310, the control circuit 30 determines whether the measured value of the q-axis current Iq_m is greater than or equal to the second current threshold TH_I2.

[0324] The second current threshold TH_I2 is used to determine whether to migrate to the mid-migration mode M3. The second current threshold TH_I2 is set to a value greater than the first current threshold TH_I1. For example, the second current threshold TH_I2 is 30 amperes.

[0325] When the measured value of the q-axis current Iq_m is greater than or equal to the second current threshold TH_I2 (S310: YES), the control circuit 30 switches to S320 and migrates to the mid-migration mode M3.

[0326] Next, in S330, the control circuit 30 saves the current measured value of q-axis current Iq_m as the reference measured value of q-axis current Iq_hold.

[0327] Next, in S340, the control circuit 30 saves the current d-axis current command value Id_r as the d-axis current reference command value Id_hold.

[0328] After that, it ended. Figure 9 The weak excitation treatment shown.

[0329] On the other hand, in S310, if the measured value of the q-axis current Iq_m is not greater than or equal to the second current threshold TH_I2 (S310: NO), the control circuit 30 moves to S350 to determine whether the duty cycle Duty is less than the second duty cycle threshold TH_D2.

[0330] The second duty cycle threshold TH_D2 is a threshold used to determine whether the output voltage of the drive circuit 31 is saturated. For example, the second duty cycle threshold TH_D2 is 95%.

[0331] When the duty cycle Duty < the second duty threshold TH_D2 (S350: YES), the control circuit 30 switches to S320 and migrates to the mid-migration mode M3.

[0332] On the other hand, if the duty cycle Duty is not less than the second duty cycle threshold TH_D2 (S350: NO), the control circuit 30 ends. Figure 9 The weak excitation treatment shown.

[0333] Thus, in the weak excitation mode M2, the control circuit 30 increases or decreases the d-axis current command value Id_r based on the difference between the measured q-axis current value Iq_m and the q-axis current command value Iq_r. Furthermore, the control circuit 30 transitions to the mid-transition mode M3 based on predetermined conditions (i.e., the conditions in S310 and S350).

[0334] [2-2-6. Handling during migration]

[0335] use Figure 10 The flowchart below illustrates the mid-migration processing performed by the control circuit 30. Mid-migration processing refers to the processing performed by the control circuit 30 in mid-migration mode M3.

[0336] First, in S400, control circuit 30 calculates the MTPA current value Id_mtpa. The calculation method for the MTPA current value Id_mtpa is the same as in S200.

[0337] Next, in S405, the control circuit 30 determines whether the measured value of the q-axis current Iq_m is greater than or equal to the second current threshold TH_I2.

[0338] When the measured q-axis current value Iq_m ≥ the second current threshold TH_I2 (S405: YES), the control circuit 30 transitions to S410, setting the d-axis current command value Id_r = d-axis current reference command value Id_hold + (slope m × (q-axis current measured value Iq_m - q-axis current reference measured value Iq_hold)). In the mid-migration mode M3, the slope m represents the slope of the trajectory of the d-axis current command value Id_r in the d-q coordinate system. This will be described in detail later. In this embodiment, the slope m is set to 0. That is, it is set as: d-axis current command value Id_r = d-axis current reference command value Id_hold.

[0339] Next, in S415, the control circuit 30 determines whether the d-axis current command value Id_r is greater than the MTPA current value Id_mtpa.

[0340] If the d-axis current command value Id_r is not greater than the MTPA current value Id_mtpa (S415: NO), then control circuit 30 ends. Figure 10The migration process shown is handled midway.

[0341] On the other hand, when the d-axis current command value Id_r > MTPA current value Id_mtpa (S415: YES), the control circuit 30 switches to S420 and sets the d-axis current command value Id_r = MTPA current value Id_mtpa.

[0342] Next, in S425, control circuit 30 transitions to MTPA mode M1. After this, the process ends. Figure 10 The migration process shown is handled midway.

[0343] On the other hand, if the measured value of the q-axis current Iq_m is not greater than or equal to the second current threshold TH_I2 (S405: NO), the control circuit 30 switches to S430 to determine whether the duty cycle Duty is less than the second duty cycle threshold TH_D2.

[0344] If the duty cycle Duty is not less than the second duty cycle threshold TH_D2 (S430: NO), the control circuit 30 switches to S435, adding the gain × (measured q-axis current value Iq_m - q-axis current command value Iq_r) to the d-axis current command value Id_r. The processing of S435 is the same as that of S300.

[0345] Next, in S440, the control circuit 30 determines whether the measured value of the q-axis current Iq_m is less than the first current threshold TH_I1.

[0346] If the measured q-axis current value Iq_m is not less than the first current threshold TH_I1 (S440: NO), control circuit 30 ends. Figure 10 The migration process shown is handled midway.

[0347] On the other hand, when the measured q-axis current Iq_m < the first current threshold TH_I1 (S440: YES), control circuit 30 switches to S445, transitioning to weak excitation mode M2. After this, the process ends. Figure 10 The migration process shown is handled midway.

[0348] On the other hand, when the duty cycle Duty < the second duty threshold TH_D2 (S430: YES), the control circuit 30 switches to S450, incrementing the d-axis current command value Id_r. The incremented value is, for example, 0.01 amperes.

[0349] Next, in S455, the control circuit 30 determines whether the d-axis current command value Id_r is greater than the MTPA current value Id_mtpa.

[0350] If the d-axis current command value Id_r is not greater than the MTPA current value Id_mtpa (S455: NO), then control circuit 30 ends. Figure 10 The migration process shown is handled midway.

[0351] On the other hand, when the d-axis current command value Id_r > MTPA current value Id_mtpa (S455: YES), the control circuit 30 switches to S460 and sets the d-axis current command value Id_r = MTPA current value Id_mtpa.

[0352] Next, in S465, control circuit 30 transitions to MTPA mode M1. After this, the process ends. Figure 10 The migration process shown is handled midway.

[0353] Thus, in the mid-migration mode M3, when the measured q-axis current value Iq_m ≥ the second current threshold TH_I2 (S405: YES), the control circuit 30 sets the d-axis current command value Id_r based on the d-axis current reference command value Id_hold and the measured q-axis current value Iq_m. Furthermore, when the d-axis current command value Id_r > the MTPA current value Id_mtpa (S415: YES), the control circuit 30 migrates to the MTPA mode M1.

[0354] On the other hand, if the measured value of the q-axis current Iq_m is not greater than or equal to the second current threshold TH_I2 (S405: NO), the control circuit 30 determines, based on the specified conditions (i.e., the conditions of S430, S440, and S455), whether to migrate to MTPA mode M1 or weak excitation mode M2, or to continue migrating to intermediate mode M3.

[0355] [2-2-7. Regeneration Process]

[0356] use Figure 11 The flowchart below illustrates the regeneration process performed by the control circuit 30. The regeneration process refers to the processing performed by the control circuit 30 in regeneration mode M4.

[0357] First, in S500, control circuit 30 increments the d-axis current command value Id_r. The increment is, for example, 0.01 amperes.

[0358] Next, in S510, the control circuit 30 determines whether the d-axis current command value Id_r > 0.

[0359] If the d-axis current command value Id_r > 0, control circuit 30 switches to S520 and sets the d-axis current command value Id_r = 0. Afterward, control circuit 30 switches to S530.

[0360] On the other hand, if the d-axis current command value Id_r is not greater than 0, the control circuit 30 switches to S530.

[0361] Next, in S530, the control circuit 30 determines whether the q-axis current command value Iq_r > 0.

[0362] When the q-axis current command value Iq_r > 0, control circuit 30 switches to S540 and transitions to MTPA mode M1. After this, control circuit 30 terminates. Figure 11 The regeneration process is shown.

[0363] On the other hand, if the q-axis current command value Iq_r is not greater than 0, the control circuit 30 terminates. Figure 11 The regeneration process is shown.

[0364] Thus, in regenerative mode M4, control circuit 30 increments the d-axis current command value Id_r until Id_r > 0. When the d-axis current command value Id_r is incremented and exceeds 0, control circuit 30 sets the d-axis current command value Id_r = 0.

[0365] Furthermore, when the q-axis current command value Iq_r > 0, the control circuit 30 switches to MTPA mode M1.

[0366] [2-2-8. Trajectory of the current vector in the d-q coordinate system]

[0367] Figure 12 The diagram shows: the current trajectory 60 in the d-q coordinate system, the induced voltage limiting ellipse 61, the MTPF curve 62, the constant torque curve 63, the MTPA curve 64, and the current limiting circle 65. Figure 12 In the d-q coordinate system, the d-axis represents the axis of the d-axis current Id, and the q-axis represents the axis of the q-axis current Iq.

[0368] The current trajectory 60 is the trajectory of the commanded value of the current vector I. In Figure 12 In the diagram, the current trajectory 60 is represented by a solid line. However, the trajectory during the acceleration phase of motor 6 is omitted.

[0369] When the motor 6 disengages from the acceleration state and the control circuit 30 transitions from MTPA mode M1 to weak excitation mode M2, the current vector I is located at point 60a.

[0370] As the torque of motor 6 increases with the pull of trigger 10, the magnitude of current vector I increases. The trajectory of current vector I as torque increases is explained below.

[0371] The current vector I migrates along the induced voltage limiting ellipse 61 on the path Pab from point 60a to intersection point 60b. Intersection point 60b is the intersection of the induced voltage limiting ellipse 61 and the MTPF curve 62.

[0372] The induced voltage limiting ellipse 61 is represented by the following equations (2) to (6).

[0373]

Mathematical Formula 2

[0374]

[0375]

Mathematical Expression 3

[0376]

[0377]

Mathematical Expression 4

[0378]

[0379]

Mathematical Expression 5

[0380]

[0381]

Mathematical Expression 6

[0382]

[0383] In equations (2) to (6), Vom is the maximum induced voltage amplitude [V]. ω is the rotational speed of motor 6 (i.e., rotor 19) [rpm]. Vam is the maximum voltage output amplitude [V]. Ra is the winding resistance [Ω]. Vo is the induced voltage [V]. Va is the voltage vector [V] according to the voltage equation in equation (5). Ia is the current vector I [A]. φ is the current phase delay angle (in other words, the delay angle from the voltage phase) [rad]. The units in parentheses are an example.

[0384] MTPF is an abbreviation for Maximum Torque Per Flux. MTPF curve 62 is the trajectory of the current vector I that maximizes the torque of motor 6 per unit flux. That is, in the d-q coordinate system, MTPF curve 62 is the set of points where the maximum torque per unit flux is obtained.

[0385] The MTPF curve 62 is represented by the following formulas (7) to (8).

[0386]

Mathematical Expression 7

[0387]

[0388]

Mathematical Expression 8

[0389]

[0390] In equations (7) to (8), Ψ0 is the magnitude of the magnetic flux vector of the magnetic body in rotor 19.

[0391] On path Pab, control circuit 30 controls the current vector I in a way that prevents it from being set outside the induced voltage limiting ellipse 61. For example, when the command value of current vector I is set outside the induced voltage limiting ellipse 61, control circuit 30 reduces the d-axis current Id of current vector I, so that current vector I is set inside the induced voltage limiting ellipse 61, including its boundary. The command value of current vector I is also called the current command value. The d-axis component of the current command value is the d-axis current command value Id_r. The q-axis component of the current command value is the q-axis current command value Iq_r. The control on path Pab is also called constant rotation control of motor 6. On path Pab, control circuit 30 operates in weak excitation mode M2.

[0392] The current vector I migrates along the MTPF curve 62 on the path Pbc from intersection point 60b to intersection point 60c. Intersection point 60c is the intersection of the MTPF curve 62 and the specified constant torque curve 63. On path Pbc, the control circuit 30 performs so-called MTPF control. On path Pbc, the control circuit 30 operates in a weak excitation mode M2.

[0393] The constant torque curve 63 is represented by the following equation (9).

[0394]

Mathematical Expression 9

[0395]

[0396] In equation (9), the torque T is a constant value. Pn is the number of pole pairs of motor 6.

[0397] The current vector I migrates linearly along the path Pcd from intersection point 60c to intersection point 60d, corresponding to a slope m. When the slope m = 0, the d-axis current Id of the current vector I remains unchanged. Intersection point 60d is the intersection of the straight line passing through intersection point 60c and the MTPA curve 64. The MTPA curve 64 is represented by the above equation (1). That is, the MTPA curve 64 is the set of points in the d-q coordinate system that yields the maximum torque per unit current.

[0398] The slope m is set to such that path Pcd lies in the region closer to the positive q-axis than the constant torque curve 63. Alternatively, the slope m can be set to such that path Pcd lies in the region closer to the positive q-axis than the MTPF curve 62.

[0399] The q-axis component of intersection 60c corresponds to the second current threshold TH_I2. That is, on path Pcd, control circuit 30 operates in mid-migration mode M3.

[0400] In this embodiment, since the slope m = 0, the path Pcd is a line segment parallel to the q-axis.

[0401] The current vector I migrates along the MTPA curve 64 on the path Pde from intersection point 60d to intersection point 60e. Intersection point 60e is the intersection of the MTPA curve 64 and the current limiting circle 65. On the path Pde, the control circuit 30 operates in MTPA mode M1.

[0402] The current limiting circle 65 is a circle representing the upper limit of the magnitude of the current vector I. The current limiting circle 65 is represented by the following equation (10).

[0403]

Mathematical Expression 10

[0404]

[0405] In equation (10), Iam is a constant value representing the upper limit of the magnitude of the current vector I. In this embodiment, Iam is set to the upper limit of the bus current, Ib_limit.

[0406] [2-2-9. Relationship between speed and torque]

[0407] exist Figure 13 In the figure, the N-T characteristic 70, which represents the relationship between the rotational speed N and the torque T of the motor 6, shows the first N-T characteristic 71, the second N-T characteristic 72, and the third N-T characteristic 73.

[0408] The first N-T characteristic 71 is: the N-T characteristic when controlling the motor 6 in this embodiment.

[0409] The second N-T characteristic 72 is: the N-T characteristic when the motor 6 is controlled by a normal rectangular wave.

[0410] The third N-T characteristic 73 is: the N-T characteristic when performing normal vector control on motor 6.

[0411] The maximum speed of a typical rectangular wave control is greater than that of a typical vector control. The maximum torque of a typical rectangular wave control is less than that of a typical vector control.

[0412] In contrast, the maximum speed controlled in this embodiment is higher than the maximum speed of typical rectangular wave control. The maximum torque controlled in this embodiment is higher than the maximum torque of typical vector control.

[0413] In this embodiment, when the torque T of the motor 6 is less than the second torque constant T2, the control circuit 30 operates in a weak excitation mode M2. However, when the torque T is less than the first torque constant T1, the control circuit 30 performs constant rotational control at a speed N1. At this time, the speed N in the first N-T characteristic 71 is greater than the speed N in both the second N-T characteristic 72 and the third N-T characteristic 73.

[0414] In the interval where the second torque constant T2 ≤ torque T < the third torque constant T3, the control circuit 30 operates in the mid-migration mode M3.

[0415] When the torque T = the second torque constant T2, the rotational speed N in the first N-T characteristic 71 is approximately the same as the rotational speed N2 in the second N-T characteristic 72.

[0416] When the torque T = the third torque constant T3, the rotational speed N in the first N-T characteristic 71 is approximately the same as the rotational speed N3 in the third N-T characteristic 73.

[0417] At this time, the control circuit 30 controls the current vector I in a manner that prevents the product of the speed N and torque T, which is the output of the motor 6, from changing drastically. For example, the control circuit 30 controls the current vector I in a manner that the first N-T characteristic 71 changes along a straight line connecting (N2, T2) and (N3, T3). Alternatively, when N2 × T2 = N3 × T3 is satisfied, the control circuit 30 controls the current vector I in a manner that changes along an inverse proportional curve passing through (N2, T2) and (N3, T3).

[0418] In the interval where the third torque constant T3 ≤ torque T ≤ the fourth torque constant T4, the control circuit 30 operates in MTPA mode M1. The fourth torque constant T4 represents the maximum torque. In this interval, the first N-T characteristic 71 is approximately the same as the third N-T characteristic 73.

[0419] [2-2-10. Relationship between rotational speed, torque, and current]

[0420] exist Figure 14 The diagram shows: T-N characteristic 80a, which represents the relationship between the torque T and the speed N of motor 6, and I-N characteristic 80b, which represents the relationship between the bus current value Ib and the speed N of motor 6.

[0421] The first T-N characteristic 81a and the second T-N characteristic 82a are shown in T-N characteristic 80a.

[0422] The first I-N characteristic 81b and the second I-N characteristic 82b are shown in I-N characteristic 80b.

[0423] The first T-N characteristic 81a is: the T-N characteristic when controlling the motor 6 in this embodiment.

[0424] The second T-N characteristic 82a is the trajectory of the upper limit value of the torque T in the motor 6 (hereinafter also referred to as the upper limit value of torque). The torque T in the first T-N characteristic 81a is controlled to not exceed the upper limit value of torque.

[0425] The first I-N characteristic 81b is: the trajectory of the bus current value Ib that changes with the rotational speed N of the motor 6.

[0426] Characteristic 82b of the second I-N is: the trajectory of the upper limit value of the bus current Ib_limit, which changes with the rotational speed N of the motor 6.

[0427] The bus current Ib in the first I-N characteristic 81b is controlled to not exceed the upper limit value Ib_limit of the bus current in the second I-N characteristic 82b.

[0428] At rotational speed N = N1, constant rotational control is achieved through control circuit 30, causing torque T to increase to its upper limit. The bus current Ib increases with the increase of torque T.

[0429] Once the torque T reaches its upper limit, the rotational speed N begins to decrease from N1. As the rotational speed N decreases, the torque T and the bus current Ib further increase.

[0430] When the bus current Ib exceeds the upper limit of the bus current Ib_limit, the bus current Ib is controlled to reduce it below the upper limit of the bus current Ib_limit. At this time, the rotational speed N is N2. That is, as the rotational speed N decreases from N2, the bus current Ib decreases. As the rotational speed N decreases, the torque T increases, but the increase in torque T is smaller than in the range where the rotational speed N > N2.

[0431] When the bus current Ib is lower than the upper limit of the bus current Ib_limit, the bus current Ib is controlled to increase it to the upper limit of the bus current Ib_limit. When the bus current Ib = the upper limit of the bus current Ib_limit, the speed N = N3. That is, when the speed N decreases from N2 to N3, the bus current Ib is controlled to reach the upper limit of the bus current Ib_limit. As the speed N decreases, the torque T increases.

[0432] Within the speed range N from N3 to N4, the bus current Ib and its upper limit Ib_limit remain constant. As the speed N decreases, the torque T increases.

[0433] In the speed range N < N4, the bus current Ib and its upper limit Ib_limit decrease monotonically. The decrease in bus current Ib is greater than the decrease in the upper limit Ib_limit. As speed N decreases, torque T increases, but the increase in torque T is smaller than in the speed range N > N4.

[0434] In this way, the bus current value Ib is controlled in a manner that does not exceed the upper limit of the bus current Ib_limit. The increase in torque T, which varies with rotational speed N, is affected by the increase or decrease in bus current Ib.

[0435] [2-3. Effects]

[0436] Based on the implementation methods described above, the following functions and effects can be obtained.

[0437] (2a) When transitioning from weak excitation mode M2 ​​to MTPA mode M1, control circuit 30 operates via mid-transition mode M3. For example... Figure 12 As shown, in the d-q coordinate system, the current vector I migrates linearly along the path Pcd of the control circuit 30 operating in the mid-migration mode M3, with a slope m corresponding to the slope. The slope m is set such that the path Pcd is located in a region closer to the positive q-axis than the constant torque curve 63. The slope m can also be set such that the path Pcd is located in a region closer to the positive q-axis than the MTPF curve 62.

[0438] That is, when the measured value of the q-axis current Iq_m is greater than or equal to the second current threshold TH_I2, in other words, when the measured value of the q-axis current Iq_m is contained in a region that is closer to the positive side of the q-axis than the intersection point 60c of the MTPF curve 62 and the constant torque curve 63, the current vector I is set in a region that is closer to the positive side of the q-axis than both the MTPF curve 62 and the constant torque curve 63.

[0439] Assuming that the control circuit 30 migrates from the weak excitation mode M2 ​​to the MTPA mode M1 without passing through the intermediate migration mode M3, the current vector I in the d-q coordinate system is as follows: Figure 12 As shown, the curve moves from intersection point 60c on MTPF curve 62 to intersection point 60f on MTPA curve 64. Intersection point 60f is the intersection of constant torque curve 63 and MTPA curve 64.

[0440] At this time, the N-T characteristic 70 is as follows Figure 13As shown, with the torque T = T2 remaining constant, the rotational speed N decreases sharply from N2 to N2a. Rotational speed N2a is the rotational speed N at torque T = T2 in characteristic 73 of the third N-T series. When the torque T remains constant while the rotational speed N decreases sharply, the product of the rotational speed N and the torque T, which is the output of the motor 6, changes drastically. Therefore, the stability of the motor 6's operation decreases.

[0441] In contrast, according to the processing of this embodiment, during the transition from weak excitation mode M2 ​​to MTPA mode M1—in other words, during the switch from weak excitation control to normal vector control—a mid-transition mode M3 is used to suppress abrupt changes in the output of the motor 6. Since the path Pcd in the d-q coordinate system corresponding to mid-transition mode M3 is located in a region closer to the positive q-axis than both the MTPF curve 62 and the constant torque curve 63, the torque T is not abruptly reduced during the transition to MTPA mode M1. This improves the stability of the motor 6's output.

[0442] (2b) In the mid-migration mode M3, if the d-axis current command value Id_r > the MTPA current value Id_mtpa (S415: YES), the control circuit 30 sets the d-axis current command value Id_r = the MTPA current value Id_mtpa (S420), and migrates to the MTPA mode M1 (S425). In other words, in Figure 12 In the d-q coordinate system, the current vector I migrates along the path Pcd and the path Pde.

[0443] Based on this processing, the control circuit 30 can control the current vector I along the MTPA curve 64 when the q-axis current Iq increases.

[0444] (2c) When the control circuit 30 transitions from the weak excitation mode M2 ​​to the mid-transition mode M3, it saves the current measured value of the q-axis current Iq_m as the q-axis current reference measured value Iq_hold (S330) and saves the current command value of the d-axis current Id_r as the d-axis current reference command value Id_hold (S340).

[0445] In the mid-migration mode M3, when the measured value of the q-axis current Iq_m is greater than or equal to the second current threshold TH_I2 (S405: YES), the control circuit 30 sets the d-axis current command value Id_r based on the measured value of the q-axis current reference Iq_hold and the d-axis current reference command value Id_hold (S410).

[0446] Based on this processing, the d-axis current command value Id_r in the mid-migration mode M3 can be set using the measured q-axis current value Iq_m and the d-axis current command value Id_r at the time point of transition from the weak excitation mode M2 ​​to the mid-migration mode M3. This allows for the suppression of abrupt changes in the current vector I.

[0447] (2d) The control circuit 30 migrates between multiple modes based on the measured q-axis current value Iq_m. That is, the control circuit 30 migrates from MTPA mode M1 to weak excitation mode M2 ​​(S250) when the measured q-axis current value Iq_m < the first current threshold TH_I1. The control circuit 30 migrates from weak excitation mode M2 ​​to mid-migration mode M3 (S320) when the measured q-axis current value Iq_m ≥ the second current threshold TH_I2 (S310: YES). The control circuit 30 can migrate from mid-migration mode M3 to MTPA mode M1 or weak excitation mode M2 ​​depending on whether the measured q-axis current value Iq_m ≥ the second current threshold TH_I2 (S405).

[0448] Based on the second trigger signal TR2 corresponding to the pulling amount of the trigger 10 manually operated by the user, the measured value of the q-axis current Iq_m is calculated by the instruction unit 43 and the speed control unit 44.

[0449] Based on this processing, the operating mode of the control circuit 30 can be switched according to the amount of pull of the trigger 10 manually operated by the user. Therefore, the control circuit 30 can operate in the optimal operating mode corresponding to the amount of pull of the trigger 10.

[0450] (2e) in Figure 12 On the path Pab in the d-q coordinate system shown, the control circuit 30 controls the current vector I so that it is not set outside the induced voltage limiting ellipse 61. The control on the path Pab is the constant rotation control of the motor 6. The control circuit 30 performs constant rotation control based on the above equations (2) to (6). That is, the control circuit 30 performs constant rotation control based on both the q-axis current Iq and the d-axis current Id.

[0451] Based on this processing, instead of relying solely on the q-axis current Iq, an appropriate current vector I is set based on both the q-axis current Iq and the d-axis current Id, thereby enabling constant rotation control.

[0452] (2f) When the control circuit 30 inputs the bus current detection signal Sib, the upper limit value of the bus current Ib_limit, and the measured value of the d-axis current Id_m through the limit value calculation unit 46, it calculates the d-axis current limit value Id_limit. Specifically, the d-axis current limit value Id_limit is calculated based on the difference between the bus current value Ib represented by the bus current detection signal Sib and the upper limit value of the bus current Ib_limit.

[0453] Based on this configuration, the d-axis current command value Id_r can be dynamically controlled based on the bus current value Ib, without exceeding the upper limit of the bus current value Ib_limit.

[0454] (2g) In the mid-migration mode M3, the control circuit 30 migrates to the MTPA mode M1 (S425) with the condition that the measured value of the q-axis current Iq_m is greater than or equal to the second current threshold TH_I2.

[0455] On the other hand, in the mid-migration mode M3, the control circuit 30 migrates to the weak excitation mode M2 ​​(S445) with the condition that the measured value of the q-axis current Iq_m < the first current threshold TH_I1 (S440: YES). The first current threshold TH_I1 is set to a value smaller than the second current threshold TH_I2.

[0456] Based on this processing, after the control circuit 30 has just transitioned from the weak excitation mode M2 ​​to the mid-transition mode M3, even if the measured q-axis current value Iq_m is lower than the second current threshold TH_I2, as long as it is above the first current threshold TH_I1, it will suppress the transition from the mid-transition mode M3 to the weak excitation mode M2. Therefore, even if the measured q-axis current value Iq_m changes around the second current threshold TH_I2, it can prevent the repeated transitions between the mid-transition mode M3 and the weak excitation mode M2 ​​from exceeding the necessary limit.

[0457] (2h) such as Figure 13 As shown, in the range where the torque T of the N-T characteristic 70 is less than the second torque constant T2, the control circuit 30 operates in the weak excitation mode M2. In the weak excitation mode M2, the control circuit 30 performs so-called weak excitation control.

[0458] Based on this processing, the rotational speed N in this embodiment is greater than the rotational speed N of both typical rectangular wave control and typical vector control. Therefore, the maximum rotational speed of motor 6 can be increased.

[0459] [2-4. Correspondence between terms]

[0460] In the above embodiments, control circuit 30 corresponds to an example of a control circuit, current vector I corresponds to an example of current, and q-axis current command value Iq_r and d-axis current command value Id_r correspond to examples of current command values. MTPF curve 62 corresponds to an example of a maximum flux efficiency curve, and MTPA curve 64 corresponds to an example of a maximum current efficiency curve. MTPA mode M1 corresponds to an example of mode 1, weak excitation mode M2 ​​corresponds to an example of mode 2, and mid-migration mode M3 corresponds to an example of mode 3. Second current threshold TH_I2 corresponds to an example of a specified threshold, q-axis current reference measured value Iq_hold corresponds to an example of a reference measured value, and d-axis current reference command value Id_hold corresponds to an example of a reference command value. Bus current Ib corresponds to an example of power supply current, bus current upper limit value Ib_limit corresponds to an example of an upper limit value of power supply current, and d-axis current limit value Id_limit corresponds to an example of an upper limit value of the d-axis component of the current command value.

[0461] [3. Second Embodiment]

[0462] [3-1. Composition]

[0463] The basic structure of the electric work machine 1 in the second embodiment is the same as that in the electric work machine 1 of the first embodiment. Therefore, the differences between the second embodiment and the first embodiment will be explained below. The same reference numerals as in the first embodiment indicate the same components, as can be seen from the preceding description.

[0464] The electric work machine 1 in the second embodiment includes Figure 15 The power transmission unit 207 shown is used instead of the power transmission unit 7 in the first embodiment described above.

[0465] The power transmission unit 207 is directly or indirectly connected to the motor 6 (specifically, the rotor 19). See reference. Figure 2 The power transmission unit 207 includes: multiple shaft components 207sh, a gear mechanism 207a that reduces the rotation of the motor 6 transmitted to the saw chain 9, and a sprocket 207sp configured for mounting the saw chain 9.

[0466] Specifically, the gear mechanism 207a is connected to the motor 6 via the shaft component 207sh. The sprocket 207sp is connected to the gear mechanism 207a via the shaft component 207sh.

[0467] The power transmission unit 207 transmits the rotation of the motor 6 (specifically, the rotation of the rotor 19) to the saw chain 9 via multiple shaft components 207sh, a gear mechanism 207a, and a sprocket 207sp, thereby driving the saw chain 9. When the motor 6 is driven, the saw chain 9 moves along the periphery of the guide bar 8. Accordingly, the saw chain 9 can work on the workpiece. Specifically, the saw chain 9 can cut workpieces such as wood, metal, and resin.

[0468] The gear mechanism 207a includes two gears 207g with different numbers of teeth. The gear mechanism 207a reduces the rotation of the motor 6 transmitted to the saw chain 9 by the difference in the number of teeth of the two gears 207g. The degree of reduction in rotation by the gear mechanism 207a depends on the gear ratio of the two gears 207g. For example, when the gear ratio is 1 / 2, the rotation of the motor 6 transmitted to the saw chain 9 is reduced to half the rotational speed of the motor 6.

[0469] The following describes two different implementation methods A and B, with different set values ​​for motor 6, using specific set values ​​as examples.

[0470] [3-1-1. Setting values ​​for the second embodiment A]

[0471] Embodiment 2A is an example in which the maximum output of motor 6 is approximately 2 to 3 [kW]. For example, the output of motor 6 may also be in the range of 1.7 [kW] to 2.7 [kW].

[0472] <Gear Ratio>

[0473] The gear ratio is set to a value within the specified range.

[0474] As an example of Embodiment 2A, the gear ratio can be in the range of 1 / 2.8 to 1 / 1.6, or in the range of 1 / 2.4 to 1 / 2.0. In this case, the maximum speed of the motor 6 can be 30,000 rpm or more.

[0475] For example, if the gear 207g connected to the motor 6 has 13 teeth and the gear 207g connected to the sprocket 207sp has 27 teeth, the gear ratio is 13 / 27 ≒ 1 / 2.08. This gear ratio is within the aforementioned range.

[0476] As another example, the gear ratio can be in the range of 1 / 3.73 to 1 / 2.13 or in the range of 1 / 3.20 to 1 / 2.67. In this case, the maximum speed of motor 6 can be above 40,000 rpm.

[0477] That is, the gear ratio can be in the range of 1 / 3.73 to 1 / 1.60.

[0478] <Diameter, Stack Thickness, Volume>

[0479] like Figure 16 As shown, the motor diameter φ (the diameter of motor 6), the stacking thickness LT of stator 17, and the volume of motor 6 are set to values ​​within a specified range.

[0480] As an example, the motor diameter φ can be in the range of 40 [mm] to 80 [mm], 46 [mm] to 72 [mm], or 52 [mm] to 68 [mm].

[0481] The stack thickness LT can be in the range of 12 [mm] to 40 [mm], 16 [mm] to 35 [mm], or 20 [mm] to 30 [mm].

[0482] The volume of motor 6 can be 15000 mm. 3 ] ~202000 [mm 3 Within the range of ], it can also be within 50000 [mm] 3 ~150000 [mm] 3 Within the range of ], it can also be within 80000 [mm] 3 ~120000 [mm] 3 Within the range of ].

[0483] <Quality>

[0484] The mass of the main body of the electric work machine 1 can be configured to reach a value within a specified range. The mass of the main body of the electric work machine 1 is the mass of the electric work machine 1 after deducting the battery pack 15 (including the battery 15a), the saw chain 9, and the oil used for the saw chain 9.

[0485] As an example of the second embodiment A, the mass of the main body of the electric work machine 1 can be configured to be in the range of 2.5 [kg] to 5.0 [kg], in the range of 3.0 [kg] to 4.5 [kg], or in the range of 3.2 [kg] to 4.0 [kg].

[0486] [3-1-2. Setting values ​​for the second embodiment B]

[0487] Embodiment B is an example where the maximum output of motor 6 is approximately 3 to 4 [kW]. For example, the output of motor 6 may be in the range of 3.0 [kW] to 4.0 [kW].

[0488] Even in the second embodiment B, similar to the second embodiment A, the gear ratio, diameter, stack thickness, volume, mass, etc. can be set to be within a specified range.

[0489] <Gear Ratio>

[0490] As an example of Embodiment B, the gear ratio can be in the range of 1 / 3.0 to 1 / 1.8 or in the range of 1 / 2.6 to 1 / 2.2. In this case, the maximum speed of the motor 6 can be 30,000 rpm or more.

[0491] As another example, the gear ratio can be in the range of 1 / 4.00 to 1 / 2.40 or in the range of 1 / 3.47 to 1 / 2.93. In this case, the maximum speed of motor 6 can be above 40,000 rpm.

[0492] That is, the gear ratio can also be in the range of 1 / 4.00 to 1 / 1.80.

[0493] <Diameter, Stack Thickness, Volume>

[0494] As an example of the second implementation method B Figure 16 The motor diameter φ shown can be in the range of 50 [mm] to 90 [mm], 65 [mm] to 100 [mm], or 75 [mm] to 120 [mm]. That is, the motor diameter φ can be in the range of 50 [mm] to 120 [mm].

[0495] The stack thickness LT can be in the range of 10 [mm] to 50 [mm], 15 [mm] to 40 [mm], or 20 [mm] to 30 [mm].

[0496] The volume of motor 6 can be 85000 [mm] 3 ~115600 [mm] 3 Within the range of ], it can also be within 95000 [mm] 3 ~130000 [mm] 3 Within the range of ], it can also be within 107000 [mm] 3 ~145000 [mm] 3 Within the range of ].

[0497] <Quality>

[0498] As an example of the second embodiment B, the mass of the main body of the electric work machine 1 can be in the range of 5.0 [kg] to 7.0 [kg], or in the range of 4.0 [kg] to 6.5 [kg], or in the range of 4.5 [kg] to 6.0 [kg].

[0499] [3-2. Relationship between speed, output, current, and voltage relative to torque]

[0500] [3-2-1. Characteristics of Embodiment A]

[0501] Figure 17 The actual N-T characteristic 91a, actual P-T characteristic 92a, actual I-T characteristic 93a, and actual V-T characteristic 94a of the motor 6 when controlled in this embodiment are shown.

[0502] Actual N-T characteristic 91a represents an example of the measured relationship between the rotational speed N [rpm] and torque T [N·m] of motor 6.

[0503] Actual P-T characteristic 92a represents an example of the measured relationship between the motor output P [W] and the torque T [N·m] of the motor 6.

[0504] Actual I-T characteristic 93a represents an example of the measured relationship between bus current value Ib [A] and torque T [N·m].

[0505] Actual V-T characteristic 94a represents an example of the measured relationship between power supply voltage Vc [V] and torque T [N·m].

[0506] like Figure 17 As shown, the control circuit 30 controls the motor 6 in such a way that the maximum torque of the motor 6 (that is, the maximum value of the torque T) reaches 4.0 [N·m] or more.

[0507] The control circuit 30 controls the motor 6 to achieve a maximum speed (i.e., the maximum value of speed N) of 10,000 rpm or higher. Preferably, the control circuit 30 controls the motor 6 to achieve a maximum speed of 11,000 rpm or higher. More preferably, the control circuit 30 controls the motor 6 to achieve a maximum speed of 12,000 rpm or higher.

[0508] The control circuit 30 controls the motor 6 such that the torque T is in the range of 1.5 [N·m] to 4.0 [N·m] and the motor output P is in the range of 1.7 [kW] to 2.6 [kW].

[0509] Motor 6 is displayed Figure 17When the characteristics shown are as described, the chain speed [m / s] during the driving of the saw chain 9 is 20 [m / s] or more. Preferably, the chain speed [m / s] during the driving of the saw chain 9 is 24 [m / s] or more. That is, the control circuit 30 controls the motor 6 in such a way that the chain speed [m / s] during the driving of the saw chain 9 reaches 20 [m / s] or more. Preferably, the control circuit 30 controls the motor 6 in such a way that the chain speed [m / s] during the driving of the saw chain 9 reaches 24 [m / s] or more.

[0510] [3-2-2. Characteristics of Embodiment B]

[0511] Figure 18 The actual N-T characteristic 91b, actual P-T characteristic 92b, actual I-T characteristic 93b, and actual V-T characteristic 94b of the motor 6 under control in this embodiment are shown. Figure 18 The characteristics shown are: with Figure 17 The characteristics of different types of motors 6 are shown.

[0512] Actual N-T characteristic 91b represents an example of the measured relationship between the rotational speed N [rpm] and torque T [N·m] of motor 6.

[0513] Actual P-T characteristic 92b represents an example of the measured relationship between motor output P [W] and torque T [N·m].

[0514] The Actual I-T Characteristic 93b represents an example of the measured relationship between the bus current value Ib [A] and the torque T [N·m].

[0515] Actual V-T characteristic 94b represents an example of the measured relationship between power supply voltage Vc [V] and torque T [N·m].

[0516] like Figure 18 As shown, the control circuit 30 controls the motor 6 in such a way that the maximum torque of the motor 6 (that is, the maximum value of the torque T) reaches 6.0 [N·m] or more.

[0517] The control circuit 30 controls the motor 6 to achieve a maximum speed (i.e., the maximum value of speed N) of 11,000 rpm or higher. Preferably, the control circuit 30 controls the motor 6 to achieve a maximum speed of 12,000 rpm or higher.

[0518] The control circuit 30 controls the motor 6 such that the torque T is in the range of 3.5 [N·m] to 6.0 [N·m] and the motor output P is in the range of 3.0 [kW] to 4.0 [kW].

[0519] Motor 6 is displayed Figure 18 When the characteristics shown are as described, the chain speed [m / s] during the driving of the saw chain 9 is 20 [m / s] or more. Preferably, the chain speed [m / s] during the driving of the saw chain 9 is 24 [m / s] or more. That is, the control circuit 30 controls the motor 6 in such a way that the chain speed [m / s] during the driving of the saw chain 9 reaches 20 [m / s] or more. Preferably, the control circuit 30 controls the motor 6 in such a way that the chain speed [m / s] during the driving of the saw chain 9 reaches 24 [m / s] or more.

[0520] [3-3. Effects]

[0521] According to the second embodiment detailed above, the same effects as those of the first embodiment (2a) to (2h) can be obtained. In addition, according to the second embodiment, the following effects and functions can be obtained.

[0522] (3a) The control circuit 30 controls the motor 6 by performing vector control and weak excitation control. The electric work machine 1 is in the form of an electric chainsaw.

[0523] Based on this configuration, a chainsaw can be made capable of outputting high torque T and increasing the speed N of motor 6 when torque T is low.

[0524] (3b) The power transmission unit 207 includes a gear mechanism 207a. The gear mechanism 207a reduces the rotation of the motor 6 transmitted to the saw chain 9 by means of the gear ratio of the two gears 207g.

[0525] With this configuration, the current flowing into motor 6 will not fluctuate significantly, and the torque T of motor 6 will increase by slowing down the rotation transmitted from motor 6 to saw chain 9. This ensures a high torque T and reduces power consumption during operation.

[0526] [4. Third Embodiment]

[0527] [4-1. Composition]

[0528] The basic structure of the electric work machine 301 in the third embodiment is the same as that of the electric work machine 1 in the first embodiment. Therefore, the differences between the third embodiment and the first embodiment will be explained below. The same reference numerals as in the first embodiment indicate the same components; please refer to the preceding description.

[0529] like Figures 19-23 As shown, the electric cutting machine 301 of the third embodiment is in the form of an electric circular saw (hereinafter simply referred to as a circular saw), which is another example of the electric cutting machine 1 of the first embodiment. The circular saw is used as a portable cutting machine. The circular saw can be, for example, a sliding circular saw, a cutting circular saw, etc.

[0530] Electric work machine 301 has Figures 19-23 The housing 302 shown is used to replace the housing 2 of the first embodiment described above.

[0531] The housing 302 has a battery assembly 303 at its rear. The battery assembly 303 is the same as the battery assembly 3 in the first embodiment described above.

[0532] The electric work machine 301 has a handle 304 on the upper part of the housing 302. The handle 304 is held by the user of the electric work machine 301.

[0533] The trigger 310 is disposed on the lower side of the handle 304. The trigger 310 is the same as the trigger 10 of the first embodiment described above.

[0534] The housing 302 includes a controller housing 302a and a motor housing 302b. The controller housing 302a is located below the handle 304. The motor housing 302b is located below the controller housing 302a.

[0535] like Figure 20 as well as Figure 23 As shown, the controller housing 302a houses the controller 313 inside. The basic configuration of the controller 313 is the same as that of the controller 13 in the first embodiment described above. That is, the controller 313 includes the same control circuit 30 as in the first embodiment described above.

[0536] The controller 313 is housed inside the housing 313a. For example... Figure 21 as well as Figure 23 As shown, a heat sink 351 is provided on the upper surface of the housing 313a. Multiple heat sink fins are provided on the heat sink 351. Each heat sink fin extends upward from the upper surface of the housing 313a at the same height as the others. Each heat sink fin is configured to extend along the left-right direction and to be arranged at approximately equal intervals parallel to the front-back direction.

[0537] like Figure 20 as well as Figure 23 As shown, the motor housing 302b houses the motor 6 and the power transmission unit 307 inside.

[0538] The basic structure of the power transmission unit 307 is the same as that of the power transmission unit 7 in the first or second embodiment described above. For example... Figure 23As shown, the power transmission unit 307 is directly or indirectly connected to the motor 6 (specifically, the rotor 19). Instead of the saw chain 9 of the first embodiment described above, the power transmission unit 307 is directly or indirectly connected to the circular plate-shaped cutter 309. The power transmission unit 307 includes: a gear mechanism 307a that reduces the rotation of the motor 6 transmitted to the cutter 309; and a plurality of shaft components 307sh configured for mounting the motor 6 or the cutter 309. The basic configurations of the gear mechanism 307a and the shaft components 307sh are the same as those of the gear mechanism 207a and shaft components 207sh of the second embodiment described above. The power transmission unit 307 transmits the rotation of the motor 6 (specifically, the rotation of the rotor 19) to the cutter 309 via the gear mechanism 307a and the plurality of shaft components 307sh, thereby driving the cutter 309.

[0539] like Figure 19 as well as Figure 20 As shown, the electric work machine 301 has a secondary grip 305 at the front of the motor housing 302b. The secondary grip 305 is held by the user. For example, the user can use the electric work machine 301 while holding the handle 304 with one hand (e.g., right hand) and the secondary grip 305 with the other hand (e.g., left hand). The handle 304 is, for example, made of resin. The secondary grip 305 is, for example, made of resin.

[0540] The electric workpiece 301 has a tool housing 308 on the right side of the outer casing 302. The tool housing 308 is configured to cover approximately half of the upper circumference of the tool 309. The thickness direction of the tool 309 is parallel to the left-right direction.

[0541] like Figure 19 , Figure 22 ,as well as Figure 23 As shown, the controller housing 302a has an air inlet 352 on its right side. The air inlet 352 is positioned opposite the left side of the tool housing 308. The air inlet 352 has a plurality of slits extending in the front-rear direction. The interior space of the controller housing 302a communicates with the exterior of the electric work machine 301 through the plurality of slits of the air inlet 352.

[0542] The motor housing 302b has an exhaust port 354 on its right side. The exhaust port 354 is positioned opposite the left side of the tool housing 308. The exhaust port 354 has a plurality of slits extending in the front-rear direction. The internal space of the motor housing 302b communicates with the outside of the electric work machine 301 through the plurality of slits of the exhaust port 354.

[0543] like Figure 23As shown, the portion of the controller housing 302a on the motor housing 302b side has a first opening 302c. The portion of the motor housing 302b on the controller housing 302a side has a second opening 302d. The internal space of the motor housing 302b communicates with the internal space of the controller housing 302a through the aforementioned first and second openings 302c and 302d.

[0544] like Figure 23 As shown, a cooling fan 353 is mounted on the shaft component 307sh connected to the motor 6. The cooling fan 353 rotates in response to the rotation of the motor 6. When the cooling fan 353 is started by the motor 6, outside air is introduced as cooling air CA from the air inlet 352 toward the interior of the controller housing 302a.

[0545] Cooling air CA flows into the motor housing 302b through the first and second openings 302c and 302d from inside the controller housing 302a. At this time, the cooling air CA passes between the multiple heat sinks of the radiator 351, cooling the radiator 351.

[0546] Next, cooling air CA passes through the motor housing 302b and is discharged from the exhaust port 354 toward the outside of the motor housing 302b. At this time, cooling air CA passes by the motor 6 and cools the motor 6.

[0547] In this way, the outside air introduced into the interior of the housing 2 through the air inlet 352 is used as cooling air CA and passes through the interior of the housing 2 (that is, the interior of the controller housing 302a and the motor housing 302b) and is discharged from the exhaust port 354 toward the outside of the housing 2. As the cooling air CA passes through the interior of the housing 2, it cools the radiator 351, the motor 6, etc.

[0548] [4-2. Relationship between speed, output, current, and voltage relative to torque]

[0549] <Characteristics of the motor side>

[0550] Figure 24 The actual N-T characteristics 391a, 3391a, actual P-T characteristics 392a, 3392a, actual I-T characteristics 393a, 3393a, and actual V-T characteristics 394a, 3394a of the motor 6 when the motor 6 is controlled in the third embodiment are shown.

[0551] Actual N-T characteristics 391a and 3391a represent examples of measured values ​​of the relationship between the rotational speed N [rpm] and torque T [N·m] of motor 6.

[0552] Actual P-T characteristics 392a and 3392a represent examples of measured values ​​of the relationship between the motor output P [W] and the torque T [N·m] of the motor 6.

[0553] The actual I-T characteristics 393a and 3393a represent examples of measured values ​​of the relationship between the bus current value Ib [A] and the torque T [N·m].

[0554] The actual V-T characteristics 394a and 3394a represent examples of measured values ​​of the relationship between the power supply voltage Vc [V] and the torque T [N·m].

[0555] Figure 24 The actual N-T characteristic 391a, actual P-T characteristic 392a, actual I-T characteristic 393a, and actual V-T characteristic 394a shown by the solid lines represent an example of the measured values ​​when the control circuit 30 performs weak excitation control. Figure 24 The actual N-T characteristic 3391a, actual P-T characteristic 3392a, actual I-T characteristic 3393a, and actual V-T characteristic 3394a shown by the dashed lines represent an example of the measured values ​​when the control circuit 30 does not perform weak excitation control.

[0556] like Figure 24 As shown, the control circuit 30 controls the motor 6 in such a way that the maximum torque of the motor 6 (that is, the maximum value of the torque T) reaches 1.0 [N·m] or more.

[0557] The control circuit 30 controls the motor 6 to achieve a maximum speed (i.e., the maximum value of speed N) of 28,000 rpm or higher. Preferably, the control circuit 30 controls the motor 6 to achieve a maximum speed of 30,000 rpm or higher.

[0558] The control circuit 30 controls the motor 6 such that the torque T is in the range of 0.3 [N·m] to 0.7 [N·m] and the maximum speed of the motor 6 reaches 28,000 [rpm] or more. Preferably, the control circuit 30 controls the motor 6 such that the torque T is in the range of 0.3 [N·m] to 0.7 [N·m] and the maximum speed of the motor 6 reaches 30,000 [rpm] or more.

[0559] The control circuit 30 controls the motor 6 such that the bus current value Ib is in the range of 100 [A] to 200 [A], the torque T reaches 0.3 [N·m] to 0.7 [N·m], and the motor speed 6 reaches 28,000 [rpm] or higher. Preferably, the control circuit 30 controls the motor 6 such that the bus current value Ib is in the range of 100 [A] to 200 [A], the torque T reaches 0.3 [N·m] to 0.7 [N·m], and the motor speed 6 reaches 30,000 [rpm] or higher.

[0560] The control circuit 30 can control the motor 6 in a manner where the bus current value Ib is in the range of 100 [A] to 140 [A], the torque T reaches 0.3 [N·m] to 0.5 [N·m], and the speed of the motor 6 reaches 30,000 [rpm] or more.

[0561] <Properties of the cutting tool side>

[0562] Figure 25 The diagram shows the actual N-T characteristics 391b, 3391b, actual P-T characteristics 392b, 3392b, actual I-T characteristics 393b, 3393b, and actual V-T characteristics 394b, 3394b of the tool 309 driven by the motor 6 when the motor 6 is controlled in the third embodiment.

[0563] Actual N-T characteristics 391b and 3391b represent examples of measured values ​​of the relationship between the output speed N_out [rpm] from motor 6 to tool 309 and the output torque T_out [N·m] from motor 6 to tool 309.

[0564] Actual P-T characteristics 392b and 3392b represent examples of measured values ​​of the relationship between motor output P [W] and output torque T_out [N·m].

[0565] The actual I-T characteristics 393b and 3393b represent examples of measured values ​​of the relationship between the bus current value Ib [A] and the output torque T_out [N·m].

[0566] The actual V-T characteristics 394b and 3394b represent examples of measured values ​​of the relationship between the power supply voltage Vc [V] and the output torque T_out [N·m].

[0567] Figure 25 The actual N-T characteristic 391b, actual P-T characteristic 392b, actual I-T characteristic 393b, and actual V-T characteristic 394b shown by the solid lines represent an example of the measured values ​​when the control circuit 30 performs weak excitation control. Figure 25The actual N-T characteristic 3391b, actual P-T characteristic 3392b, actual I-T characteristic 3393b, and actual V-T characteristic 3394b shown by the dashed lines represent an example of the measured values ​​when the control circuit 30 performs weak excitation control.

[0568] like Figure 25 As shown, the control circuit 30 controls the motor 6 in such a way that the maximum torque of the motor 6 (that is, the maximum value of the output torque T_out) reaches 5.5 [N·m] or more.

[0569] The control circuit 30 controls the motor 6 such that its maximum output speed (i.e., the maximum value of the output speed N_out) reaches 5500 rpm or more. Preferably, the control circuit 30 controls the motor 6 such that its maximum output speed reaches 6000 rpm or more.

[0570] The control circuit 30 controls the motor 6 such that the torque T is in the range of 2.0 [N·m] to 3.5 [N·m] and the maximum speed of the motor 6 reaches 5500 [rpm] or more. Preferably, the control circuit 30 controls the motor 6 such that the torque T is in the range of 2.0 [N·m] to 3.5 [N·m] and the maximum speed of the motor 6 reaches 6000 [rpm] or more.

[0571] The control circuit 30 controls the motor 6 such that the bus current value Ib is in the range of 100 [A] to 200 [A], the torque T reaches 2.0 [N·m] to 3.5 [N·m], and the motor speed reaches 5500 [rpm] or higher. Preferably, the control circuit 30 controls the motor 6 such that the bus current value Ib is in the range of 100 [A] to 200 [A], the torque T reaches 2.0 [N·m] to 3.5 [N·m], and the motor speed reaches 6000 [rpm] or higher.

[0572] The control circuit 30 can control the motor 6 in a manner where the bus current value Ib is in the range of 100 [A] to 140 [A], the torque T reaches 1.8 [N·m] to 2.8 [N·m], and the speed of the motor 6 reaches 6000 [rpm] or higher.

[0573] [4-3. Effects]

[0574] According to the third embodiment detailed above, the same effects as those of the first embodiment (2a) to (2h) can be obtained. In addition, according to the third embodiment, the following effects and functions can be obtained.

[0575] (4a) The control circuit 30 controls the motor 6 by performing weak excitation control. The electric work machine 301 is in the form of an electric circular saw.

[0576] Based on this configuration, a circular saw capable of outputting high torque T and increasing the motor speed N when torque T is low can be achieved. In particular, as... Figure 24 as well as Figure 25 As shown, relative to the same rotational speed N or output rotational speed N_out, a higher torque T or output torque T_out can be achieved than when weak excitation control is not performed.

[0577] (4b) The power transmission unit 307 includes a gear mechanism 307a. Similar to the first embodiment, the gear mechanism 307a reduces the rotation of the motor 6 transmitted to the cutter 309 by means of the gear ratio of the two gears.

[0578] With this configuration, the current flowing into motor 6 will not fluctuate significantly, and the torque T of motor 6 will increase by reducing the rotational speed transmitted from motor 6 to cutter 309. This ensures a high torque T and reduces power consumption during operation.

[0579] (4c) The air inlet 352 of the controller housing 302a is configured to face the side of the tool housing 308.

[0580] With this configuration, the tool housing 308 can prevent dust or dirt from flowing into the controller housing 302a from the air inlet 352. This improves the dustproof performance of the controller housing 302a.

[0581] (4d) The exhaust port 354 of the motor housing 302b is configured to face the side of the tool housing 308.

[0582] With this configuration, the tool housing 308 can prevent dust or dirt from flowing into the motor housing 302b from the exhaust port 354. This improves the dustproof performance of the motor housing 302b.

[0583] (4e) The electric work machine 301 is equipped with a cooling fan 353. The cooling fan 353 introduces outside air as cooling air CA from the air inlet 352 toward the interior of the controller housing 302a. The cooling air CA cools the heat sink 351 inside the controller housing 302a. The heat sink 351 is located in the housing 313a that houses the controller 313.

[0584] With this configuration, the heat sink 351 is cooled by cooling air CA, thereby cooling the housing 313a and the controller 313 together with the heat sink 351. This improves the heat dissipation efficiency of the controller 313.

[0585] Furthermore, cooling air CA flows into the motor housing 302b through the first and second openings 302c and 302d within the controller housing 302a. Cooling air CA is then discharged from the exhaust port 354 towards the outside of the motor housing 302b through the exhaust port 354. At this time, cooling air CA passes beside the motor 6.

[0586] With this configuration, the motor 6 can be cooled by cooling air CA. This improves the heat dissipation efficiency of the motor 6.

[0587] [5. Other implementation methods]

[0588] While the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various forms can be adopted.

[0589] (5a) In the above embodiment, the control circuit 30 repeats the operation at a constant period. Figure 5 The interrupt handling is shown. Interrupt handling is executed sequentially up to S10 to S80. However, the order of interrupt handling is not limited to this. For example, the processing of S10, S20, and S30 can be executed in any order, and some or all of them can be executed in parallel.

[0590] (5b) In the above embodiment, since the slope m is set to 0, the result is as shown in the figure. Figure 12 In the d-q coordinate system, the path Pcd in the current trajectory 60 is a line segment parallel to the q-axis. However, the slope m can also be a value other than 0.

[0591] (Example 1) The case where the slope m > 0

[0592] like Figure 26 As shown, the path Pcd is a trajectory in the region closer to the positive side of the q-axis than the constant torque curve 63, where the d-axis current Id increases as the q-axis current Iq increases.

[0593] (Example 2) The case where the slope m < 0

[0594] like Figure 27 As shown, the path Pcd is as follows: in the region closer to the positive side of the q-axis than both the constant torque curve 63 and the MTPF curve 62, the d-axis current Id decreases as the q-axis current Iq increases.

[0595] At this point, path Pcd can be a path from intersection point 60c to intersection point 160d. Intersection point 160d is the intersection of the straight line passing through intersection point 60c and the current limiting circle 65. Furthermore, path Pde can be a path from intersection point 160d to intersection point 60e. The current vector I is controlled to migrate along the current limiting circle 65 on the path Pde from intersection point 160d to intersection point 60e.

[0596] Or, such as Figure 28 As shown, the current vector I can also be controlled to migrate from path Pab along path Pbd without passing through path Pcd. Path Pbd is the path from intersection point 260b to intersection point 260d. Intersection point 260d is the intersection of MTPA curve 64 and current limiting circle 65. Intersection point 260b is the intersection of the straight line passing through intersection point 260d and the induced voltage limiting ellipse 61. Intersection point 260b is located in the region further towards the positive d-axis than current limiting circle 65.

[0597] At this point, the d-axis current Id on path Pcd can be controlled to a value below -100 [A]. In other words, the magnitude (i.e., absolute value) of the d-axis current Id on path Pcd can also be controlled to a value above 100 [A].

[0598] (5c) In the above embodiment, the current vector I migrates linearly along the path Pcd from intersection 60c to intersection 60d in a manner corresponding to the slope m. However, the current vector I is not limited to linearly increasing along the path Pcd; it may also migrate in a region closer to the positive side of the q-axis than both the constant torque curve 63 and the MTPF curve 62.

[0599] (5d) In the above embodiment, in S410, the control circuit 30 is set to the d-axis current command value Id_r = d-axis current reference command value Id_hold + (slope m × (q-axis current measured value Iq_m - q-axis current reference measured value Iq_hold)). However, the d-axis current command value Id_r in S410 is not limited to this value. The control circuit 30 can set the d-axis current command value Id_r based on the q-axis current command value Iq_r and the d-axis current command value Id_r in a manner that increases the magnitude of the current vector I in a region closer to the positive side of the q-axis than both the constant torque curve 63 and the MTPF curve 62.

[0600] (5e) In the above embodiment, the front handle 4 may be made of resin. The rear handle 5 may also be made of resin. The guide rod 8 may also be made of resin.

[0601] (5f) In the above embodiment, the battery 15a housed in the battery pack 15 may have a single cell with a tabless structure. The rated voltage of the battery 15a may be, for example, 18 [V] or 36 [V].

[0602] Based on this configuration, the heat generation of the 15A battery can be reduced through the tabless structure.

[0603] (5g) In the above embodiment, the wire diameters of the power line Lp and the ground line Ln can each be 2.5 mm or more. The wire diameters of the first to third leads 26 to 28 can each be 2.5 mm or more.

[0604] With this configuration, the resistance of the power line Lp, the ground line Ln, and the first to third leads 26 to 28 is lower than when the wire diameter is less than 2.5 mm. This reduces the heat generated when current flows through the power line Lp, the ground line Ln, and the first to third leads 26 to 28.

[0605] The power line Lp and ground line Ln, and leads 1 to 3, 26 to 28, are examples of power supply leads and motor leads.

[0606] (5h) In the above embodiment, the control circuit 30 is preferably used to control the motor 6 in such a way that the voltage phase of the voltage applied to the motor 6 is 60 degrees or more and 90 degrees or less.

[0607] (5i) In the above embodiment, the control circuit 30 performs weak excitation control through the weak excitation control unit 45. However, the weak excitation control performed by the control circuit 30 is not limited to control based on the processing of the weak excitation control unit 45. That is, the control circuit 30 may perform weak excitation control by other methods besides the weak excitation control unit 45, or alternatively.

[0608] (5j) In the above embodiment, the control circuit 30 controls the motor 6 by performing weak excitation control. At this time, the motor 6 mounted on the chainsaw, which is the electric work machine 1, can display... Figure 17 or Figure 18 That characteristic. The motor 6, mounted on the circular saw which is the electric work machine 301, can display... Figure 24 or Figure 25 That kind of characteristic.

[0609] However, the control circuit 30 may not perform weak excitation control so that the motor 6 displays... Figure 17 or Figure 18 or Figure 24 or Figure 25 Motor 6 is controlled in a manner that reflects those characteristics.

[0610] For example, the control circuit 30 can control the motor 6 mounted on the chainsaw in such a way that the maximum torque of the motor 6 reaches 4.0 [N·m] or more and the chain speed [m / s] when the saw chain 9 is driven reaches 20 [m / s] or more or 24 [m / s] or more.

[0611] Alternatively, the control circuit 30 can control the motor 6 mounted on the circular saw in such a way that the bus current value Ib is in the range of 100 [A] to 200 [A] and the torque T reaches 0.3 [N·m] to 0.7 [N·m] and the speed of the motor 6 reaches 28,000 [rpm] or more or 30,000 [rpm] or more.

[0612] (5k) In the above embodiments, the multiple functions of one constituent element can be implemented by multiple constituent elements, and the single function of one constituent element can be implemented by multiple constituent elements. The multiple functions of multiple constituent elements can be implemented by one constituent element, and the single function implemented by multiple constituent elements can be implemented by one constituent element. A portion of the structure of the above embodiments may be omitted. At least a portion of the structure of the above embodiments may be added to or replaced by other structures of the above embodiments.

[0613] (5l) In addition to the control circuit 30 described above, the present invention can be implemented in various forms. For example, it can be implemented in the form of a system with the control circuit 30 as a component, a computer program that enables the computer to function as the control circuit 30, a non-transferable physical storage medium such as a semiconductor memory that stores the computer program, a control method, etc.

[0614] [6. Other options]

[0615] [6-1. Problems that other solutions aim to solve]

[0616] In chainsaws or circular saws equipped with motors capable of outputting high torque, there is a tendency for the motor speed to decrease when the output torque of the motor is low.

[0617] One aspect of the present invention is to increase the motor speed in a saw chain or circular saw equipped with a motor capable of outputting high torque when the motor output torque is low.

[0618] [6-2. Technical Ideas of Other Solutions]

[0619] In the above description, the present invention provides the following technical concept of other solutions.

[0620] [Option 1]

[0621] A chainsaw comprising:

[0622] A motor having a stator and a rotor, and configured to receive power from a power source to rotate the rotor;

[0623] The control circuit is configured to control the motor by performing vector control and field weakening control; and

[0624] The power transmission unit is configured to drive the saw chain by transmitting the rotation of the rotor to the saw chain.

[0625] The power transmission unit includes a gear mechanism that reduces the rotation transmitted to the saw chain.

[0626] The control circuit is configured to control the motor in a manner that enables the maximum torque of the motor to reach 4.0 [N·m] or more and enables the speed of the saw chain to reach 20 [m / s] or more.

[0627] [Option 2]

[0628] According to the chainsaw described in Scheme 1, wherein,

[0629] The control circuit is configured to control the motor in a manner that enables the maximum speed of the motor to reach 10,000 rpm or more.

[0630] [Option 3]

[0631] According to the chainsaw described in Scheme 1 or Scheme 2, wherein,

[0632] The gear ratio of the gear mechanism is in the range of 1 / 3.73 to 1 / 1.60.

[0633] [Option 4]

[0634] According to any one of Schemes 1 to 3, the chainsaw wherein,

[0635] The diameter of the motor is 40 mm or more and 80 mm or less.

[0636] The stator has a stack thickness of 12 mm or more and 40 mm or less.

[0637] [Option 5]

[0638] The chainsaw according to any one of Schemes 1 to 4, wherein,

[0639] The weight of the main body of the chainsaw is more than 2.5 kg and less than 5.0 kg.

[0640] [Option 6]

[0641] According to the chainsaw described in Scheme 1 or Scheme 2, wherein,

[0642] The gear ratio of the gear mechanism is in the range of 1 / 4.00 to 1 / 1.80.

[0643] [Option 7]

[0644] According to the chainsaw described in Scheme 1, Scheme 2, or Scheme 6, wherein,

[0645] The diameter of the motor is 50 mm or more and 120 mm or less.

[0646] The stator thickness is 10 mm or more and 50 mm or less.

[0647] [Option 8]

[0648] According to the chainsaw described in Scheme 1, Scheme 2, Scheme 6, or Scheme 7, wherein,

[0649] The weight of the main body of the chainsaw is between 5.0 kg and 7.0 kg.

[0650] [Option 9]

[0651] The chainsaw according to any one of Schemes 1 to 8, wherein,

[0652] The motor is an internal rotor type brushless DC motor.

[0653] [Option 10]

[0654] The chainsaw according to any one of schemes 1 to 9, wherein,

[0655] The chainsaw also includes: a guide rod for mounting the saw chain, and a handle for the user to hold.

[0656] At least one of the guide rod and the handle is made of resin.

[0657] [Option 11]

[0658] The chainsaw according to any one of Schemes 1 to 10, wherein,

[0659] The rated voltage of the power supply is 36 [V].

[0660] [Option 12]

[0661] A circular saw, comprising:

[0662] A motor having a stator and a rotor, and configured to receive power from a power source to rotate the rotor;

[0663] The housing contains the motor.

[0664] The control circuit is configured to control the motor by performing weak excitation control;

[0665] The power transmission unit is configured to drive the cutting tool by transmitting the rotation of the rotor to the cutting tool;

[0666] A tool housing that covers the tool; and

[0667] A battery assembly section capable of assembling a battery pack that serves as the power source.

[0668] The rated voltage of the power supply is 18 [V].

[0669] [Option 13]

[0670] A circular saw, comprising:

[0671] A motor having a stator and a rotor, and configured to receive power from a power source to rotate the rotor;

[0672] The housing contains the motor.

[0673] The control circuit is configured to control the motor by performing weak excitation control;

[0674] The power transmission unit is configured to drive the cutting tool by transmitting the rotation of the rotor to the cutting tool;

[0675] A tool housing that covers the tool; and

[0676] A battery assembly section capable of assembling a battery pack that serves as the power source.

[0677] The control circuit is configured to control the motor such that, when the bus current supplied from the power source to the motor is 100 [A] or more and 200 [A] or less, the torque output by the motor is 0.3 [N·m] or more and 0.7 [N·m] or less, and the speed of the motor is 30,000 [rpm] or more and 32,000 [rpm] or less.

[0678] [Option 14]

[0679] According to the circular saw described in Scheme 13, wherein...

[0680] The rated voltage of the power supply is 18 [V].

[0681] [Option 15]

[0682] The circular saw according to any one of Schemes 12 to 14, wherein,

[0683] The control circuit is configured to control the motor in such a way that the voltage phase of the voltage applied to the motor is between 60 degrees and 90 degrees.

[0684] [Option 16]

[0685] The circular saw according to any one of Schemes 12 to 15, wherein,

[0686] The control circuit is configured to control the motor in such a way that the magnitude of the d-axis current in the weak excitation control reaches 100 [A] or more.

[0687] [Option 17]

[0688] The circular saw according to any one of Schemes 12 to 16, wherein,

[0689] The control circuit is electrically connected to the power source via a power supply lead and to the motor via a motor lead.

[0690] The diameter of both the power supply lead and the motor lead is 2.5 mm or more.

[0691] [Option 18]

[0692] The circular saw according to any one of Schemes 12 to 17, wherein,

[0693] A heat sink is provided in the control circuit.

[0694] [Option 19]

[0695] The circular saw according to any one of Schemes 12 to 18, wherein,

[0696] The circular saw also includes an air inlet located opposite the side of the tool housing and disposed on the outer casing.

[0697] [Option 20]

[0698] According to the circular saw described in Scheme 19, wherein...

[0699] The circular saw also includes a cooling fan disposed within the housing and rotated by the motor.

[0700] The cooling fan is configured to introduce cooling air from the air inlet toward the housing for cooling the control circuit.

[0701] [Option 21]

[0702] The circular saw according to any one of Schemes 12 to 20, wherein,

[0703] The battery pack contains batteries.

[0704] The battery has a single cell with a tabless structure.

Claims

1. An electric work machine, characterized in that, The electric work machine includes: a motor having a stator and a rotor, configured to receive power from a power source and be driven; and a control circuit. The stator is configured to generate a magnetic field through the flow of electric current. The rotor has a magnetic body and is configured to rotate about a rotation axis in response to changes in the magnetic field. The current has a d-axis component as a component of the d-axis and a q-axis component as a component of the q-axis in a d-q coordinate system with mutually orthogonal d-axis and q-axis. The control circuit is configured to: (i) control the motor such that the current corresponding to the current command value flows into the stator; and (ii) if the measured value of the q-axis component is located in a region closer to the positive side of the q-axis than the intersection of the constant torque curve and the maximum flux efficiency curve, the current command value is set in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve. In the d-q coordinate system, the maximum flux efficiency curve is the set of points where the maximum torque per unit flux is obtained.

2. The electric work machine according to claim 1, characterized in that, The control circuit is configured such that, when the measured value of the q-axis component is contained in a region closer to the positive side of the q-axis than the intersection point, the current command value is set in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve, and closer to the negative side of the q-axis than the maximum current efficiency curve. In the d-q coordinate system, the maximum current efficiency curve is the set of points where the maximum torque per unit current is obtained.

3. An electric work machine, characterized in that, The electric work machine includes: a motor having a stator and a rotor, configured to receive power from a power source and be driven; and a control circuit. The stator is configured to generate a magnetic field through the flow of electric current. The rotor has a magnetic body and is configured to rotate about a rotation axis in response to changes in the magnetic field. The control circuit is configured as follows: (i) The motor is controlled by shifting between multiple modes, including mode 1, mode 2, and mode 3, and operating in one of the multiple modes to allow the current corresponding to the current command value to flow into the stator. (ii) In the first mode, the current command value is set in a manner that maximizes the torque per unit current. (iii) In the second mode, the current command value is set in such a way that the magnetic field is generated in the direction that cancels out the magnetic flux generated by the magnetic body. (iv) When migrating from the second mode to the first mode, the operation is performed via the third mode. (v) When migrating from the second mode to the third mode, the measured value of the current flowing through the stator and the current command value are saved as the reference measured value and the reference command value, respectively. (vi) The current command value in the third mode is set based on at least one of the reference measured value and the reference command value.

4. The electric work machine according to claim 3, characterized in that, The control circuit is configured to set the current command value in the third mode based on the difference between the reference measured value and the measured value of the current, and the reference command value.

5. The electric work machine according to claim 3 or 4, characterized in that, The current has a d-axis component as a component of the d-axis and a q-axis component as a component of the q-axis in a d-q coordinate system with mutually orthogonal d-axis and q-axis. The control circuit is configured to migrate from the second mode to the third mode when the measured value of the q-axis component reaches or exceeds a specified threshold.

6. The electric work machine according to claim 5, characterized in that, The control circuit is configured such that, in the third mode, the current command value is set in the region of the d-q coordinate system that is closer to the positive side of the q axis than the constant torque curve.

7. The electric work machine according to claim 5 or 6, characterized in that, The control circuit is configured to migrate between the plurality of modes based on the measured values ​​of the q-axis component.

8. The electric work machine according to any one of claims 1, 2, 5 to 7, characterized in that, The control circuit is configured to use the d-axis component of the current command value to perform constant rotation control to maintain the motor speed at a constant value.

9. The electric work machine according to claim 8, characterized in that, The constant rotation control includes a process that reduces the d-axis component of the current command value.

10. The electric work machine according to claim 9, characterized in that, The constant rotation control includes a process of reducing the d-axis component of the current command value in order to set the current command value within the region of the induced voltage limiting ellipse in the d-q coordinate system.

11. The electric work machine according to any one of claims 1, 2, 5 to 10, characterized in that, The control circuit is configured to: (i) acquire the measured value of the power supply current supplied from the power source and the upper limit value of the power supply current; and (ii) calculate the upper limit value of the d-axis component of the current command value based on the measured value of the power supply current and the upper limit value of the power supply current.

12. The electric work machine according to claim 11, characterized in that, The control circuit is configured to calculate the upper limit of the d-axis component of the current command value by multiplying the difference between the measured value of the power supply current and the upper limit value of the power supply current plus 1 by the measured value of the d-axis component.

13. An electric work machine, characterized in that, The electric work machine includes: a motor having a stator and a rotor, configured to receive power from a power source and be driven; and a control circuit. The stator is configured to generate a magnetic field through the flow of electric current. The rotor has a magnetic body and is configured to rotate about a rotation axis in response to changes in the magnetic field. The control circuit is configured as follows: (i) The motor is controlled by shifting between multiple modes, including mode 1, mode 2, and mode 3, and operating in one of the multiple modes to allow the current corresponding to the current command value to flow into the stator. (ii) In the first mode, the current command value is set in a manner that maximizes the torque per unit current. (iii) In the second mode, the current command value is set in such a way that the magnetic field is generated in the direction that cancels out the magnetic flux generated by the magnetic body. (iv) When migrating from the second mode to the first mode, the operation is performed via the third mode. (v) In the third mode, the current command value is set in such a way that the torque of the motor increases while the speed of the motor decreases.

14. A control method for controlling a motor having a stator and a rotor. Its features are, The control method includes the following steps: The motor is controlled such that a current corresponding to the current command value flows into the stator; and In a d-q coordinate system with mutually orthogonal d-axis and q-axis, if the measured value of the q-axis component, which is the q-axis component of the current, is located in a region closer to the positive side of the q-axis than the intersection of the constant torque curve and the maximum flux efficiency curve, then the current command value is set in a region closer to the positive side of the q-axis than both the constant torque curve and the maximum flux efficiency curve. In the d-q coordinate system, the maximum flux efficiency curve is the set of points where the maximum torque per unit flux is obtained.

15. A control method for controlling a motor having a stator and a rotor. Its features are, The control method includes the following steps: The motor is controlled in such a way that a current corresponding to the current command value flows into the stator; The motor is controlled by switching between multiple modes, including mode 1, mode 2, and mode 3, and operating in one of the multiple modes to allow the current corresponding to the current command value to flow into the stator. In the first mode, the current command value is set in a manner that maximizes the torque per unit current; In the second mode, the current command value is set in such a way that a magnetic field is generated in the direction that counteracts the magnetic flux generated by the magnetic body of the rotor; When migrating from the second mode to the first mode, the operation is performed via the third mode; When migrating from the second mode to the third mode, the measured value of the current flowing through the stator and the current command value are saved as the reference measured value and the reference command value, respectively. as well as The current command value in the third mode is set based on at least one of the reference measured value and the reference command value.

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