Control device for motor and electrically-driven propulsion device for ship

Abstract

To provide a control device for a motor comprising a circuit protection function improved in reliability in simple configuration, and an electrically-driven propulsion device for a ship.SOLUTION: A control device 10 for a motor 1 comprises: a processor 20 for generating a control command of power to be supplied to a coil 2 of the motor 1; an inverter circuit 30 for generating power to be supplied to the coil 2 of the motor 1 based on the control command of the processor 20; and a switching circuit 60, which is provided between the inverter circuit 30 and the coil 2 of the motor 1, for switching an electrified state where the inverter circuit 30 and the coil 2 are electrified and a non-electrified state where the inverter circuit 30 is electrically cut off from the coil 2. When rotation of the motor 1 is detected in a non-supply state of power to the coil 2, the processor 20 gives a first cutoff command for switching from the electrified state to the non-electrified state to the switching circuit 60.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a motor control device and an electric propulsion device for a ship. [Background technology]

[0002] Motors have been used to drive various devices. For example, electric vehicles are equipped with drive motors instead of engines. Similarly, electric propulsion devices that use motors instead of engines are also known as propulsion devices for ships.

[0003] However, when a motor is not in operation and rotated by an external force, an induced voltage is generated in the motor coil, and an overvoltage may be applied to the inverter circuit and its peripheral circuits and the battery connected to the motor coil. In this case, the inverter circuit and its peripheral circuits and the battery may be overcharged or exceed their withstand voltage, causing them to heat up, catch fire, or break down.

[0004] In this regard, Patent Document 1 describes a power conversion device that controls an inverter to consume regenerative power generated by the rotation of a motor when towing an electric vehicle, and controls the operation of a cooler to cool the heated inverter.

[0005] Although not intended for circuit protection when the motor rotates due to an external force, Patent Document 2 describes an electric power steering device that has a function of turning off a first FET group provided between the inverter and the motor and a second FET group that constitutes the inverter when an abnormality in the inverter is detected. Furthermore, in relation to an electric propulsion device for a ship, Patent Document 3 describes an electric propulsion device that aims to suppress ship rocking with a simple configuration, and when the ship is stopped, controls the electric motor to rotate with the clutch disengaged and the orientation of the electric motor's rotating shaft including an up and down component. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-176258 [Patent Document 2] JP 2009-274686 A [Patent Document 3] JP 2020-32871 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the power conversion device described in Patent Document 1 requires a cooler with excellent cooling performance to sufficiently cool the inverter that generates heat when consuming regenerative power generated by the rotation of the motor. If the cooling performance of the cooler is insufficient, the inverter circuit may break down. On the other hand, if the cooling performance of the cooler is set by prioritizing protection of the inverter circuit, this may lead to increased costs. Patent Documents 2 and 3 do not disclose a configuration for protecting the inverter circuit and its peripheral circuits from a voltage induced in the motor coil when the motor is rotated by an external force.

[0008] In view of the above circumstances, an object of at least some embodiments of the present invention is to provide a motor control device and an electric propulsion device for a ship that are equipped with a circuit protection function that is simple in configuration and highly reliable. [Means for solving the problem]

[0009] A motor control device according to at least some embodiments of the present invention includes: a processor for generating control commands for power supplied to a coil of the motor; an inverter circuit for controlling power supplied to a coil of the motor based on a control command from the processor; a switching circuit provided between the inverter circuit and a coil of the motor for switching between a current-carrying state in which the inverter circuit and the coil are electrically connected and a current-disconnecting state in which the inverter circuit is electrically disconnected from the coil; Equipped with The processor is configured to provide a first shutoff command to the switching circuit to switch from a conducting state to a non-conducting state when rotation of the motor is detected with no power being supplied to the coil. Effect of the Invention

[0010] According to at least some embodiments of the present invention, when motor rotation is detected while no power is being supplied to the motor coil, the processor issues a first shut-off command to the switching circuit, thereby electrically disconnecting the inverter circuit from the motor coil. Therefore, the inverter circuit and its peripheral circuits can be protected with a simple configuration and high reliability from the voltage induced in the motor coil when the motor is rotated by an external force. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a motor control device according to an embodiment. [Diagram 2] FIG. 4 is a schematic cross-sectional view showing an example of the configuration of a motor and a sensor. [Diagram 3] FIG. 2 is a diagram showing a configuration of a switching contact unit and its surroundings of the control device according to one embodiment. [Figure 4] 1 is a diagram showing a schematic configuration of an electric propulsion device according to one embodiment. FIG. [Diagram 5] 5 is a timing chart showing the operation of the control device according to the embodiment, illustrating a case in which the motor is not forcibly rotated by an external force. [Figure 6] 4 is a timing chart showing the operation of the control device according to the embodiment, illustrating a case in which the motor is forcibly rotated by an external force. [Figure 7] 4 is a flowchart showing a procedure for controlling a motor according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, motor control devices according to some embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, a drive motor for driving various devices is assumed as an object to be controlled by the control device. In some embodiments, the motor to be controlled is a drive motor for an electric vehicle or a motor for an electric propulsion device of a ship.

[0013] FIG. 1 is a diagram illustrating an example of the configuration of a motor control device according to an embodiment. In some embodiments, the control device 10 of the motor 1 includes a processor 20 for generating a control command for the power supplied to the coil 2 of the motor 1, and an inverter circuit 30 for controlling the power supplied to the coil 2 of the motor 1, as shown in FIG. 1.

[0014] Each part of the control device 10 can operate by receiving power supply from a battery 4. Note that each part of the control device 10 may receive power through a power switch. The control device 10 may include a control power supply circuit 40 and a switching contact unit 50 as a power supply unit for supplying power to each part of the control device 10.

[0015] The control power supply circuit 40 is provided between the processor 20 and the battery 4, and supplies power to the processor 20. In one embodiment, the control power supply circuit 40 includes an input terminal connected to the battery 4, an output terminal connected to the processor 20, and a voltage regulator provided between the input terminal and the output terminal. In this case, the voltage regulator may have a function of converting the output voltage of the battery 4 into a voltage suitable for the input of the processor 20.

[0016] The switching contact unit 50 is provided between the inverter circuit 30 and the battery 4, and is configured to switch the connection state between the inverter circuit 30 and the battery 4. The switching contact unit 50 may include, for example, either a contact switch or a contactless switch. The relay as a component of the switching contact unit 50 may be, for example, a contact switch relay or a mechanical relay that is connected by energizing a drive coil by an external signal, or a contactless switch relay may be a semiconductor relay using a semiconductor element such as a FET. The switching contact unit 50 may also include one or more main contacts provided between the inverter circuit 30 and the battery 4, and a pre-charge contact for protecting the main contact from an inrush current.

[0017] In the exemplary embodiment shown in FIG. 1, the control device 10 includes both a control power supply circuit 40 and a switching contact unit 50 . However, the switching contact unit 50 may be omitted depending on the operating conditions (rated voltage, rated current) of the inverter circuit 30. For this reason, in another embodiment, the control device 10 includes only the control power supply circuit 40 as a power supply unit. In this case, the inverter circuit 30 is directly connected to the battery 4. Furthermore, if the output voltage of the battery 4 is consistent with the input voltage to the processor 20, the control power supply circuit 40 can also be omitted. Therefore, in yet another embodiment, the control power supply circuit 40 as a power supply unit is omitted, and the processor 20 is directly connected to the battery 4.

[0018] The processor 20 is an arithmetic device that is operable by receiving power from the battery 4. In one embodiment, power is supplied from the battery 4 to the processor 20 via the control power supply circuit 40 described above. The processor 20 is, for example, a microcontroller unit (MCU) or a microprocessor Unit), etc.

[0019] The processor 20 is configured to receive an external signal ES from the upper control device 100 and control each part of the control device 10 in response to the external signal ES. In some embodiments, the external signal ES from the upper control device 100 includes a first external signal ES1 indicating a motor drive command or a motor stop command, and a second external signal ES2 for switching the connection state between the inverter circuit 30 and the battery 4. The processor 20 is configured to behave as follows in response to the external signal ES received from the upper control device 100.

[0020] When the processor 20 receives a first external signal ES1 indicating a motor drive command or a motor stop command from the upper control device 100, the processor 20 generates a control command for the inverter circuit 30 in response to the first external signal ES1.

[0021] Here, the control command to the inverter circuit 30 is a power supply command for adjusting the power supplied to the coil 2 of the motor 1. The power supply command to the inverter circuit 30 is not particularly limited, and may be, for example, a pulse width modulation (PWM) type that controls the output voltage to the coil 2 by a duty ratio. Specifically, the PWM type control command is a PWM signal based on the duty ratio calculated by the processor 20. Note that another example of the power supply command to the inverter circuit 30 is a pulse amplitude modulation (PAM) type control command.

[0022] When the processor 20 receives a motor drive command from the upper control device 100 as the first external signal ES1, the processor 20 provides a power supply command, which may be, for example, a PWM signal, to the inverter circuit 30. In contrast, when the processor 20 receives a motor stop command as the first external signal ES1, the processor 20 provides a control command to the inverter circuit 30 to stop the power supply to the coil 2 of the motor 1.

[0023] On the other hand, when the processor 20 receives a second external signal ES2 from the upper control device 100 for switching the connection state between the inverter circuit 30 and the battery 4, the processor 20 generates an operation command for the switching contact unit 50 in response to the second external signal ES2. Specifically, when the second external signal ES2 is “ON”, the processor 20 closes the switching contact unit 50 to electrically connect the inverter circuit 30 and the battery 4. In contrast, when the second external signal ES2 is “OFF”, the processor 20 opens the switching contact unit 50 to disconnect the inverter circuit 30 from the battery 4.

[0024] The inverter circuit 30 controls the power supplied to the coil 2 of the motor 1 by adjusting the output voltage or output current based on a control command from the processor 20. The inverter circuit 30 includes a semiconductor switching element that operates in response to a control command from the processor 20. Examples of the semiconductor switching element that constitutes the inverter circuit 30 include a field effect transistor (FET), an insulated gate bipolar transistor (IGBT), and the like. Bipolar Transistors, etc.

[0025] When the control command from the processor 20 is a PWM signal, the inverter circuit 30 controls the output voltage to be sinusoidal based on the PWM signal so as to realize a continuously changing duty ratio. When the pseudo-sine wave output from the inverter circuit 30 is applied to the coil 2, a current flows through the coil 2 and the motor 1 rotates.

[0026] Here, the motor 1 is a drive motor that operates in accordance with power supply control by the inverter circuit 30. When the inverter circuit 30 stops supplying power to the coil 2 of the motor 1 under the control of the processor 20, the motor 1 does not rotate.

[0027] However, even when power is not being supplied to the coil 2 of the motor 1, an external force may act on the shaft of the motor 1, causing the motor 1 to be forcibly rotated. For example, if the motor 1 is a drive motor for an electric vehicle, the motor 1 may be forcibly rotated by an external force while stopped when the electric vehicle is towed. Alternatively, if the motor 1 is an electric propulsion device for a ship, the motor 1 of the electric propulsion device may be forcibly rotated by a fluid force while the ship is sailing using another propulsion device attached to the electric propulsion device.

[0028] When the motor 1 is forcibly rotated, a voltage is induced in the coil 2 of the motor 1. This voltage is proportional to the number of rotations of the motor 1 caused by an external force. If the induced voltage in the coil 2 becomes excessive, an overvoltage is applied to the inverter circuit 30 connected to the coil 2 of the motor 1, its peripheral circuits, and the battery, which may result in overvoltage and overcharging, causing heat generation, fire, and other problems that may cause these circuits to break down.

[0029] Therefore, in some embodiments, in order to protect the inverter circuit 30 and its peripheral circuits from the voltage induced in the coil 2 when the motor 1 is forcibly rotated by an external force, the control device 10 includes a switching circuit 60 provided between the inverter circuit 30 and the coil 2 of the motor 1.

[0030] The switching circuit 60 has a function of switching between a conducting state in which the inverter circuit 30 and the coil 2 are conducting, and a non-conducting state in which the inverter circuit 30 is electrically disconnected from the coil 2. The switching circuit 60 includes a plurality of semiconductor switching elements that operate in response to control commands from the processor 20. Examples of the semiconductor switching elements that constitute the switching circuit 60 include FETs (Field Effect Transistors), IGBTs (Insulated Gate Transistors), and the like. An n-channel FET is suitable as a component element of the switching circuit 60 because it is less expensive than other switching elements. It is desirable to set the switching elements of the switching circuit 60 in consideration of the maximum induced voltage Vmax of the coil 2, which corresponds to the maximum rotation speed of the motor 1 forced to rotate due to an external force. For example, the switching circuit 60 may include switching elements having a withstand voltage equal to or greater than the maximum induced voltage Vmax of the coil 2, which corresponds to the maximum rotation speed of the motor 1 forced to rotate.

[0031] The operation of the switching circuit 60 is controlled by the processor 20 . Specifically, when rotation of the motor 1 is detected in a state where power is not supplied to the coil 2, the processor 20 provides a first cut-off command to the switching circuit 60. In response to the first cut-off command from the processor 20, the switching circuit 60 electrically cuts off the inverter circuit 30 from the coil 2.

[0032] The first shutoff command is generated autonomously by the processor 20, not by an external signal ES from the higher-level control device 100. For this reason, depending on the nature of the equipment driven by the motor 1, it may be desirable to notify the user of the equipment (for example, if the motor 1 is a motor for an electric propulsion device of a ship, the user of the electric propulsion device, i.e., the operator of the ship) of the fact that the first shutoff command has been issued. In this case, when the rotation of the motor 1 is detected in a state where power is not supplied to the coil 2, the processor 20 may provide a first shutoff command to the switching circuit 60 and output an alarm indicating the issuance of the first shutoff command. At this time, the alarm from the processor 20 may be output to a display or a warning light connected to the control device 10.

[0033] In some embodiments, as shown in FIG. 1 , the control device 10 includes a sensor 70 for detecting the rotation of the motor 1, and the processor 20 is configured to receive a detection signal ω of the rotation of the motor 1 from the sensor 70 and control the switching circuit 60 based on the detection signal ω of the sensor 70.

[0034] FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the motor 1 and the sensor 70. As shown in FIG. As shown in the figure, the motor 1 includes a rotor 80 provided with a magnet 82, and a stator 90 arranged radially opposite the rotor 80 and wound with a coil 2. The rotor 80 is rotatable together with a shaft 3 of the motor 1. In the example shown in FIG. 2, the motor 1 is an inner rotor type three-phase brushless motor. In another example, the motor 1 is an outer rotor type three-phase brushless motor.

[0035] In one embodiment, the sensor 70 may include a magnet 82 of the rotor 80 and magnetic sensors 70A to 70C for detecting the magnetic field generated by the magnet 82. In this case, the magnetic sensors 70A to 70C may be Hall elements. The Hall elements have the function of detecting the rotation of the motor 1 by detecting whether the magnetic pole of the opposing magnet 82 is an N pole or an S pole. Also, the sensor may detect the rotation by detecting an induced voltage waveform generated by the rotation of the motor 1.

[0036] In other embodiments, the sensor 70 may be a resolver or rotary encoder that detects the rotational position of the rotor 80 .

[0037] FIG. 3 is a diagram showing a configuration around the switching contact unit 50 of the control device 10 according to one embodiment.

[0038] 3, in some embodiments, the switching contact unit 50 includes a first main contact 52 provided on the positive terminal side of the battery 4, a second main contact 54 provided on the negative terminal (GND terminal) side of the battery 4, and a pre-charge contact 56 provided in parallel to the first main contact 52 and connected in series with a resistor. The pre-charge contact 56 closes before the first main contact 52, thereby charging a capacitor 58 to a predetermined voltage and protecting the first main contact 52 from an excessive inrush current. The first main contact 52, the second main contact 54, and the precharge contact 56 may be either a contact switch or a contactless switch. As components of the switching contact unit 50, for example, the relay of the contact switch may be a mechanical relay that is connected by energizing a drive coil by an external signal, and the contactless switch may be a current-carrying method using a semiconductor element such as a FET.

[0039] In some embodiments, the switching circuit 60 includes a FET 62 provided between the inverter circuit 30 and the motor 1 (coil 2). In the embodiment shown in Fig. 3, the switching circuit 60 includes three FETs 62 (62A to 62C) respectively corresponding to the three-phase coils 2 of the motor 1. Each FET 62 may be an n-channel FET. As described above, the FET 62 operates in response to a control command from the processor 20. In response to a first cutoff command from the processor 20, the switching circuit 60 electrically cuts off the inverter circuit 30 from the coil 2 by turning off the FETs 62 (62A to 62C).

[0040] In another embodiment, the switching circuit 60 includes mechanical contacts instead of the FETs 62 (62A to 62C).

[0041] FIG. 4 is a diagram showing a schematic configuration of an electric propulsion device according to one embodiment. As shown in the figure, in some embodiments, the electric propulsion device 200 includes a motor 1, a propeller 210 driven by the motor 1, and a control device 10 for controlling the motor 1. The electric propulsion device 200 also includes an attachment 202 that can be attached to the rear of the hull 221 of the vessel 220. The electric propulsion device 200 is attached to the rear of the hull 221 of the vessel 220 via the attachment 202. Note that the ship 220 is equipped with other propulsion devices (not shown) in addition to the electric propulsion device 200, and is capable of sailing using the other propulsion devices even when the operation of the electric propulsion device 200 is stopped.

[0042] The control device 10 of the electric propulsion device 200 has the processor 20, inverter circuit 30, and switching circuit 60 described above with reference to Figures 1 and 3. The control device 10 is connected to a battery 4 mounted on the hull 221, and power is supplied from the battery 4 to the processor 20 and inverter circuit 30 of the control device 10. The control device 10 may be mounted near the motor 1. The processor 20 generates a control command for the inverter circuit 30 in response to a first external signal ES1 from the upper control device 100 (see Figure 1), and issues a first shut-off command to the switching circuit 60 when rotation of the motor 1 is detected when no power is supplied to the coil 2 of the motor 1.

[0043] When the boat 220 is traveling using the electric propulsion device 200, the inverter circuit 30 responds to a first external signal ES1 to control the power supplied to the coil 2 of the motor 1, and the propeller 210 is driven by the motor 1. In contrast, when the operation of the electric propulsion device 200 is stopped and the ship 220 navigates using another propulsion device, power is not supplied to the coil 2 of the motor 1 of the electric propulsion device 200, but the propeller 210 may be subjected to a hydrodynamic force, forcing the motor 1 to rotate. In preparation for this case, the processor 20 issues a first cutoff command to the switching circuit 60 when rotation of the motor 1 is detected in a state in which power is not being supplied to the coil 2 of the motor 1. This electrically cuts off the inverter circuit 30 from the coil 2 of the motor 1, preventing the application of an induced voltage generated in the coil 2 to the inverter circuit 30.

[0044] The operation of the control device 10 will be described with reference to FIGS. Fig. 5 is a timing chart showing the operation of the control device 10 according to one embodiment, showing a case where the motor 1 is not forcibly rotated by an external force. Fig. 6 is a timing chart showing the operation of the control device 10 according to one embodiment, showing a case where the motor 1 is forcibly rotated by an external force.

[0045] Note that the timing charts in Figures 5 and 6 are based on the assumption that the control device 10 has a switching contact unit 50 having the configuration shown in Figure 3, but the presence or absence of the switching contact unit 50 and the specific configuration of the switching contact unit 50 are not limited to this example.

[0046] As shown in FIG. 5, when the power supply of the battery 4 is turned on at t=t0, power is supplied to the processor 20 via the control power supply circuit 40, and the processor 20 starts controlling each part of the control device 10. The power supply to the battery 4 may be turned on by, for example, a user of the device driven by the motor 1 via an operation unit such as an ignition key or an ignition switch.

[0047] At t=t1, the processor 20 receives an “ON” signal as the second external signal ES2 from the upper control device 100 and starts control over the switching contact unit 50. Specifically, at t=t1, the processor 20 sends a close operation command ("ON" control command) to the pre-charge contact 56 and the second main contact 54 of the switching contact unit 50. At t=t2, in response to the "ON" control command from the processor 20, the pre-charge contact 56 and the second main contact 54 of the switching contact unit 50 perform a close operation. As a result, charging of the capacitor 58 provided on the input side of the inverter circuit 30 begins, and the input voltage of the inverter circuit 30 (INV input voltage in FIG. 5) rises until it reaches the output voltage of the battery 4. When the input voltage of the inverter circuit 30 reaches a predetermined voltage, the processor 20 sends an opening command (an "OFF" control command) to the pre-charge contact 56 and a closing command (an "ON" control command) to the first main contact 52. As a result, at t=t3, the pre-charge contact 56 opens in response to the "OFF" control command from the processor 20, and the first main contact 52 closes in response to the "ON" control command from the processor 20. In this way, the electrical connection between the battery 4 and the inverter circuit 30 is completed.

[0048] In parallel with the control of the switching contact unit 50 described above, the processor 20 sends an “ON” control command to the switching circuit 60, and at t=t3, the switching circuit 60 switches to “ON” in response to the control command from the processor 20. In this way, power can be supplied from the battery 4 to the coil 2 of the motor 1 via the inverter circuit 30.

[0049] At t=t4, when the processor 20 receives an "ON" signal as the first external signal ES1 from the upper control device 100, it sends a control command (e.g., a PWM signal) to the inverter circuit 30, and in response to this, the inverter circuit 30 starts controlling the power supply to the coil 2. As a result, the motor 1 starts rotating, and the rotation of the motor 1 is detected by the sensor 70 (the motor rotation signal "ON" in FIG. 5).

[0050] At t=t5, when the processor 20 receives an "OFF" signal as the first external signal ES1 from the upper control device 100, it sends a control command to the inverter circuit 30, and in response to this, the inverter circuit 30 stops controlling the power supply to the coil 2. As a result, the rotation of the motor 1 stops, and the stop of rotation of the motor 1 is detected by the sensor 70 ("OFF" of the motor rotation signal in FIG. 5).

[0051] In addition, at t=t5, in response to an “OFF” signal as the second external signal ES2 from the higher-level control device 100, the processor 20 sends an opening control command (an “OFF” control command) to the first main contact 52 and the second main contact 54, and also sends an “OFF” control command to the switching circuit 60. As a result, at t=t6, the first main contact 52 and the second main contact 54 open, electrically disconnecting the inverter circuit 30 from the battery 4, and the switching circuit 60 also turns "OFF." After that, the capacitor 58 starts discharging, and the input voltage of the inverter circuit 30 drops to zero.

[0052] Finally, at t=t7, the power supply of the battery 4 is turned off, the power supply to the processor 20 via the control power supply circuit 40 is stopped, and the processor 20 goes into a non-operational state.

[0053] In the example shown in Figure 5, at t = t5, simultaneously with the motor 1 stopping rotation, the processor 20 receives the "OFF" signal of the second external signal ES2, and the opening operation of the first main contact 52 and the second main contact 54 is initiated immediately thereafter. 6, after the rotation of the motor 1 stops at t=t5, the second external signal ES2 is maintained at "ON" for the period t≦t18. Note that the period from t0≦t≦t5 in FIG. 6 is the same as the timing chart in FIG. 5.

[0054] 6, at t=t16, the first external signal ES1 is "OFF", and power supply to the coil 2 of the motor 1 is stopped. When the motor 1 is forcibly rotated by an external force in this state, the rotation of the motor 1 is detected by the sensor 70, and the processor 20 issues a first shutoff command to the switching circuit 60 in response to the rotation detection signal of the motor 1 from the sensor 70. As described above, since the second external signal ES2 from the upper control device 100 is maintained as "ON" at t=t16, the generation of the first shutoff command by the processor 20 is not in response to the second external signal ES2, but is due to an autonomous operation of the processor 20. After that, at t=t17, the switching circuit 60 is switched “OFF” in response to a first shutoff command, and the inverter circuit 30 is electrically shut off from the coil 2 of the motor 1.

[0055] Furthermore, at t=t16, when the processor 20 receives a rotation detection signal of the motor 1 from the sensor 70 while power is not being supplied to the coil 2, the processor 20 issues a second cutoff command to the switching contact unit 50 to cut off the connection between the inverter circuit 30 and the battery 4, regardless of the second external signal ES2. That is, at t=t16, the processor 20 sends an opening operation control command (an "OFF" control command) to the first main contact 52 and the second main contact 54. Note that the generation of the second cutoff command by the processor 20 at t=t16 is not in response to the second external signal ES2, but is due to an autonomous operation of the processor 20. After that, at t=t17, the first main contact 52 and the second main contact 54 open in response to the second cut-off command, and the inverter circuit 30 is electrically cut off from the battery 4. As a result, the capacitor 58 starts to discharge, and the input voltage of the inverter circuit 30 starts to drop.

[0056] After that, at t=t19, the power supply of the battery 4 is turned off, the power supply to the processor 20 via the control power supply circuit 40 is stopped, and the processor 20 is put into a non-operating state. Since the control device 10 stops operating thereafter, even if the motor 1 is forcibly rotated by an external force at t=t20, the control device 10 will not be controlled in response to the rotation detection signal of the sensor 70. However, since the switching contact unit 50 and the switching circuit 60 are both in the "OFF" state, the induced voltage generated in the coil 2 by the external force is not applied to the inverter circuit 30 and its peripheral circuits.

[0057] Next, a specific example of the procedure for controlling the motor 1 by the control device 10 will be described with reference to Fig. 7. However, the content described with reference to Fig. 7 is merely an example and does not limit the scope of the present invention. FIG. 7 is a flowchart showing a procedure for controlling the motor 1 according to an embodiment. In the example shown in the figure, when the switch of the 48V power supply of the battery 4 is turned ON (step S10), the control power supply circuit 40 converts the voltage from 48V to 12V, and the processor 20, which may be a microcomputer, starts up (step S12). In step S14, the processor 20, which may be a microcomputer, receives an "ON" signal as the second external signal ES2 from the upper control device 100 (step S14). The processor 20, which may be a microcomputer, starts controlling the switching contact unit 50, and turns on the pre-charge contact (pre-contactor) 56 and the second main contact 54 (GND contactor) (step S16). When the processor (microcomputer) 20 determines that the input voltage (voltage inside the board) of the inverter circuit 30 has risen to 48V, the processor (microcomputer) 20 turns on the first main contact (power supply contactor) 52 and the switch circuit (motor energizing circuit) 60 (step S18). In step S20, the processor 20 receives an "ON" signal (motor drive signal) as the first external signal ES1 from the upper control device 100. In step S22, in response to a control command from the processor (microcomputer) 20, the inverter circuit 30 starts controlling the power supply to the coil 2, and the motor 1 is driven. The rotation signal of the motor 1 is detected by the sensor 70 (step S24). When the processor 20 receives an "OFF" signal (motor stop signal) as the first external signal ES1 (step S26), the inverter circuit 30 stops driving the motor 1 in response to the control command from the processor (microcomputer) 20 (step S28). Thereafter, the state of the motor 1 is monitored by the sensor 70, and if the rotation signal of the motor 1 is less than N rpm (N in step S30), the processor (microcomputer) 20 judges whether or not an "ON" signal (motor drive signal) has been received as the first external signal ES1 from the upper control device 100 (step S32). If the motor drive signal has been received (Y in step S32), the process returns to step S22. If the motor drive signal has not been received (N in step S32), the process proceeds to step S34, where it is judged whether or not an "OFF" signal has been received as the second external signal ES2 from the upper control device 100. If the "OFF" signal has not been received as the second external signal ES2 (N in step S34), the process returns to step S28. On the other hand, if an "OFF" signal has been received as the second external signal ES2 (Y in step S34), the process proceeds to step S36, where the contactors (52, 54, 56) and the switch circuit (motor energizing circuit) 60 are turned OFF in response to a control command from the processor (microcomputer) 20. Thereafter, the processor (microcomputer) 20 judges whether or not an "ON" signal has been received as the second external signal ES2 from the upper control device 100 (step S38). If an "ON" signal has been received as the second external signal ES2 (Y in step S38), the process returns to step S16. On the other hand, if an "ON" signal has not been received as the second external signal ES2 (N in step S38), the process proceeds to step S40, where it is judged whether or not the switch of the 48V power supply of the battery 4 has been turned OFF (step S40). If the switch of the 48V power supply is turned OFF, the power supply of the battery 4 is turned OFF, the input voltage to the processor (microcomputer) 20 via the control power supply circuit 40 becomes 0V, and the processor (microcomputer) 20 stops operating (step S42). On the other hand, if the switch of the 48V power supply is not turned OFF (N in step S40), the process returns to step S38. In step S30, if the rotation signal of the motor 1 is equal to or greater than N rpm (Y in step S30), the processor (microcomputer) 20 transmits a warning signal (alarm) (step S44), and issues a first cut-off command and a second cut-off command to the switching circuit 60 and the switching contact unit 50, respectively, and the contactors (52, 54, 56) and the switch circuit (motor energizing circuit) 60 are turned OFF (step S46). After that, the state of the motor 1 is monitored by the sensor 70, and if the rotation signal of the motor 1 is greater than M rpm (N in step S48), the process returns to step S44. On the other hand, if the rotation signal of the motor 1 becomes equal to or less than M rpm (Y in step S48), the processor (microcomputer) 20 determines whether or not an alarm stop signal has been received from the upper control device 100 (step S50). If the processor (microcomputer) 20 receives the alarm stop signal (Y in step S50), it stops issuing an alarm (step S52) and proceeds to step S38. On the other hand, if the alarm stop signal is not received (N in step S50), the process returns to step S44. It is preferable that the threshold value M [rpm] of the rotation speed of the motor 1 in step S30 in step S48 is smaller than the threshold value N [rpm] of the rotation speed of the motor 1 in step S30.

[0058] The characteristic configurations of the control device 10 and the electric propulsion device 200 according to the several embodiments described above can be summarized as follows.

[0059] [1] In some embodiments, a control device (10) for a motor (1) includes: a processor (20) for generating a control command for power supplied to a coil (2) of the motor (1); an inverter circuit (30) for controlling power supplied to a coil (2) of the motor (1) based on a control command from a processor (20); a switching circuit (60) provided between the inverter circuit (30) and a coil (2) of the motor (1) for switching between a current-carrying state in which the inverter circuit (30) and the coil (2) are electrically connected and a current-disconnecting state in which the inverter circuit (30) is electrically disconnected from the coil (2); Equipped with The processor (20) is configured to, when rotation of the motor (1) is detected with no power being supplied to the coil (2), provide a first cut-off command to the switching circuit (60) for switching from a conducting state to a non-conducting state.

[0060] According to the above configuration [1], when rotation of the motor (1) is detected in a state in which power is not supplied to the motor coil (2), the inverter circuit (30) is electrically disconnected from the motor coil (2) by operation of the switching circuit (60) based on a first disconnection command from the processor (20). Therefore, the inverter circuit (30) and its peripheral circuits can be protected with a simple configuration and high reliability from the voltage induced in the motor coil (2) when the motor (1) is rotated by an external force.

[0061] [2] In some embodiments, in the configuration of [1] above, The control device (10) includes at least one switching contact unit (50) provided between the inverter circuit (30) and the battery (4); The processor (20) receiving a first external signal (ES1) indicating a drive command or a stop command for the motor (1) from a higher-level control device (100), and generating a control command for the inverter circuit (30) in response to the first external signal (ES1); receiving a second external signal (ES2) for switching a connection state between the inverter circuit (30) and the battery (4) from the upper control device (100), and operating the switching contact unit (50) in response to the second external signal (ES2); When rotation of the motor (1) is detected in a state where power is not supplied to the coil (2), a first cut-off command is given to the switching circuit (60) and a second cut-off command for cutting off the connection between the inverter circuit (30) and the battery (4) is given to the switching contact unit (50) regardless of the first external signal (ES1) and the second external signal (ES2). It is configured as follows.

[0062] In the above configuration [2], when rotation of the motor (1) is detected in a state in which power is not supplied to the coil (2), the processor (20) autonomously provides a first shut-off command and a second shut-off command to the switching circuit (60) and the switching contact unit (50), respectively, without relying on external signals (ES1, ES2). This makes it possible to more reliably protect the inverter circuit (30) and its peripheral circuits from the voltage induced in the motor coil (2) when the motor (1) is rotated by an external force.

[0063] [3] In some embodiments, in the configuration of [1] or [2] above, The switching circuit (60) includes a plurality of switching elements (semiconductor switching elements).

[0064] According to the above configuration [3], it is possible to quickly respond to the control command (second cutoff command) from the processor (20) and immediately cut off the inverter circuit (30) from the motor coil (2).

[0065] [4] In some embodiments, in any one of the configurations [1] to [3] above, The processor (20) is configured to output an alarm indicating the issuance of a first shutoff command when rotation of the motor (1) is detected in a state in which power is not supplied to the coil (2).

[0066] The first shutoff command is generated autonomously by the processor (20) without relying on an external signal (ES) from the higher-level control device (100). For this reason, depending on the nature of the equipment driven by the motor (1), it may be desirable to inform the user of the equipment of the fact that the first shutoff command has been issued. In this regard, according to the configuration [4] above, the fact that the first shutoff command has been issued can be notified to the user of the equipment by an alarm output from the processor (20). The equipment user, who has been informed by the alarm that the first shutoff command has been issued, may perform an additional operation to protect the motor (1). For example, the additional operation by the equipment user may be an operation to turn off the power supply to the battery (4) or an operation to move the motor (1) so that no external force is input to the motor (1). An example of the latter operation may be an operation to move the propeller (210) of the electric propulsion device (200) on which the motor (1) is mounted above the water surface.

[0067] [5] In some embodiments, in any one of the configurations [1] to [4] above, The control device (10) includes a sensor (70) for detecting the rotation of the motor (1); The processor (20) is configured to receive a detection signal (ω) of the rotation of the motor (1) from the sensor (70) and to control the switching circuit (60) based on the detection signal (ω).

[0068] According to the configuration [5] above, the sensor (70) can detect that the motor (1) has been forcibly rotated by an external force, and the detection signal (ω) of the sensor (70) can be used as a trigger for starting control of the switching circuit (60) in the processor (20).

[0069] [6] In some embodiments, in the configuration of [5] above, The sensor (70) a magnet (82) provided on a rotor (80) of the motor (1); a magnetic sensor (70A to 70C) for detecting a magnetic field generated by a magnet (82); Includes.

[0070] According to the configuration [6] above, the sensor (70) can be incorporated inside the motor (1), and the sensor (70) can be configured compactly and simply to detect when the motor (1) is forcibly rotated by an external force.

[0071] [7] In some embodiments, an electric propulsion system (200) for a marine vessel (220) includes: A motor (1), a propeller (210) driven by a motor (1); A control device (10) having any one of the configurations [1] to [6] above for controlling a motor (1); Equipped with.

[0072] According to the configuration [7] described above, even if the propeller (210) receives a fluid force and the motor (1) is forcibly rotated while the ship (220) is sailing using another propulsion device, the processor (20) issues a first shutoff command to the switching circuit (60), thereby making it possible to protect the inverter circuit (30) and its peripheral circuits from the voltage induced in the motor coil (2) with a simple configuration and high reliability.

[0073] Although several embodiments of the present invention have been described above, it is of course possible to add modifications to the above-described embodiments without departing from the spirit of the present invention. For example, the timing charts in Fig. 5 and Fig. 6 are based on the configuration example of the switching contact unit 50 shown in Fig. 3, but the control power supply circuit 40 and the switching contact unit 50 are not essential components. In an embodiment in which the control device 10 does not include the switching contact unit 50, the operation of the control device 10 is sufficient as long as it follows the timing charts shown in Fig. 5 and Fig. 6 for the "switching circuit", "ES1", and "motor rotation signal", and does not have to operate according to the timing charts shown in Fig. 5 and Fig. 6 including "ES2", "pre-charge contact", "second main contact", "INV input voltage", and "first main contact". In addition, in the timing charts in Fig. 5 and Fig. 6, the intervals between adjacent time points (t=t0 to t21) are shown to be equal for the sake of convenience of explanation, but the operation timing of the control device 10 is not limited to this example. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements. [Explanation of symbols]

[0074] 1: Motor 2: Coil 4: Battery 10: Control device 20: Processor 30: Inverter circuit 50: Switching contact unit 60: Switching circuit 70: Sensor 70A: Magnetic sensor 70B: Magnetic sensor 70C: Magnetic sensor 80: Rotor 82: Magnet 100: Upper control device 200: Electric propulsion device 210: Propeller 220: Ship ES1: First external signal ES2: Second external signal

Claims

1. A motor control device, comprising: a processor for generating control commands for power supplied to a coil of the motor; an inverter circuit for controlling the power supplied to the coil of the motor based on the control command of the processor; a switching circuit provided between the inverter circuit and the coil of the motor for switching between a current-carrying state in which the inverter circuit and the coil are electrically connected and a current-disconnecting state in which the inverter circuit is electrically disconnected from the coil; Equipped with The processor is configured to provide, to the switching circuit, a first interruption command for switching from the energized state to the non-energized state when rotation of the motor is detected in a state in which power is not supplied to the coil. A motor control device comprising:

2. at least one switching contact unit provided between the inverter circuit and a battery; The processor, receiving a first external signal indicating a drive command or a stop command for the motor from a higher-level control device, and generating the control command for the inverter circuit in response to the first external signal; receiving a second external signal for switching a connection state between the inverter circuit and the battery from the upper control device, and operating the switching contact unit in response to the second external signal; When rotation of the motor is detected in the state where power is not supplied to the coil, the first cutoff command is provided to the switching circuit and a second cutoff command for cutting off a connection between the inverter circuit and the battery is provided to the switching contact unit, regardless of the first external signal and the second external signal.

2. The motor control device according to claim 1, configured as follows.

3. The switching circuit includes a plurality of switching elements. The motor control device according to claim 1 or 2.

4. The processor is configured to output an alarm indicating issuance of the first shutoff command when rotation of the motor is detected in the state in which the power is not supplied to the coil. The motor control device according to claim 1 or 2.

5. a sensor for detecting rotation of the motor; The processor is configured to receive a detection signal of rotation of the motor from the sensor and to control the switching circuit based on the detection signal. The motor control device according to claim 1 or 2.

6. The sensor includes: A magnet provided on a rotor of the motor; a magnetic sensor for detecting a magnetic field generated by the magnet; Includes The motor control device according to claim 5.

7. The motor; a propeller driven by the motor; and A control device according to claim 1 or 2 for controlling the motor; An electric propulsion device for a ship.

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