Drive device and control method

Abstract

To provide a drive device and a control method capable of reducing unnecessary power supplied to a motor when starting the same.SOLUTION: A drive device uses an electric motor to drive a ship propeller. The drive device comprises an electric power converter, a control unit, and a speed reference setting unit. The electric power converter supplies electric power based on a speed control to an electric motor. The control unit causes the electric power according to the speed control result based on the rotation speed and the speed reference of the electric motor to be supplied to the electric motor. The speed reference setting unit generates the speed reference. The speed reference setting unit sets the speed reference at the magnitude according to the rotation speed of the electric motor when the rotation speed of the electric motor exceeds a first predetermined value, and determines the speed reference by the determination result obtained by determining whether or not the electric motor can be started.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drive device and a control method. [Background technology]

[0002] A marine drive device (hereinafter, simply referred to as the drive device) drives an electric motor according to a speed reference specified by its higher-level device, and rotates a propeller linked to the electric motor to generate thrust for the marine vessel. The thrust of the marine vessel can be adjusted by adjusting the speed reference of the electric motor. For example, the higher-level device specifies that the speed reference of the electric motor should be gradually increased from a speed of zero to start operation of the marine vessel. When the speed reference is set to a speed of zero or near zero, the propeller and the electric motor may rotate due to the influence of the current speed relative to the marine vessel. In the above case, the drive device may supply power to the electric motor to counteract the rotation of the electric motor according to the speed reference (a value at or near zero speed). When such a state occurs, unnecessary power may be supplied to the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-171843 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a drive device and a control method that are capable of reducing unnecessary power supplied to an electric motor when starting the motor. [Means for solving the problem]

[0005] A drive device according to one aspect of the embodiment drives a propeller of a ship with an electric motor. The drive device includes a power conversion device, a control unit, and a speed reference setting unit. The power conversion device supplies power based on speed control to the electric motor. The control unit supplies power to the electric motor according to a result of the speed control based on the rotation speed of the electric motor and a speed reference. The speed reference setting unit generates the speed reference. The speed reference setting unit sets the speed reference to a magnitude according to the rotation speed of the electric motor when the rotation speed of the electric motor exceeds a first predetermined value, and determines the speed reference according to a result of a judgment as to whether or not the electric motor can be started. [Brief description of the drawings]

[0006] [Figure 1A] FIG. 1 is a schematic configuration diagram of a drive device according to an embodiment. [Figure 1B] FIG. 2 is a configuration diagram of a drive device according to an embodiment. [Diagram 2] 4 is a flowchart of a startup process according to the embodiment. [Diagram 3] 3 is a flowchart of a process for prompting confirmation of whether or not the operation in FIG. 2 can be started. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The drive device and control method of the embodiment will be described below. In the following description, being electrically connected may simply be referred to as being "connected". The small fixed value in the embodiment may include 0. In this specification, "based on XX" means "based on at least XX" and includes the case of being based on other elements in addition to XX. Furthermore, "based on XX" is not limited to the case of directly using XX, but also includes the case of being based on XX that has been calculated or processed. "XX" is any element (for example, any information).

[0008] Fig. 1A is a schematic diagram of a drive device 1 according to an embodiment. Fig. 1B is a diagram of the drive device 1 according to an embodiment. Fig. 4 is a diagram of the control device according to an embodiment.

[0009] The drive device 1 drives the electric motor 2 according to a speed reference ω* (operation command speed reference) specified by a higher-level device 50, and rotates a propeller linked to the electric motor 2 to obtain thrust for the ship. The electric motor 2 is provided with a speed sensor 2SS that detects the speed of the electric motor 2. The speed sensor 2SS detects the speed of the electric motor 2 and outputs a rotation speed ωFB.

[0010] The drive device 1 includes a control device 10 and a power conversion device 30, for example. The drive device 1 controls the electric motor 2 using a control device 10 and a power conversion device 30.

[0011] The power conversion device 30 is an inverter that includes a plurality of semiconductor switching elements and supplies power to the electric motor 2 based on the control of the control device 10. There are no limitations on the form of the power conversion device 30 or the type of semiconductor switching elements, and any suitable one from among known ones may be used as appropriate.

[0012] The control device 10 controls the power conversion device 30 based on the result of speed control based on the rotation speed of the electric motor 2 and the speed reference ω*, and causes the power conversion device 30 to supply power according to the control result to the electric motor 2.

[0013] For example, the control device 10 can be configured by a microprocessor including a CPU (Central Processing Unit) 10a, a memory 10b, and an input / output (I / O) circuit 10c. The input / output circuit 10a receives detection values ​​from sensors disposed in the power conversion device 30 and the electric motor 2, and outputs control signals to the components of the power conversion device 30. The control signals include gate signals GP to semiconductor switching elements that are components of the power conversion device 30.

[0014] The control device 10 can realize the control functions described below by software processing in which the CPU 10a executes arithmetic processing according to a program stored in the memory 10b. Alternatively, the control device 10 can realize some or all of the control functions by hardware processing using dedicated electronic circuits.

[0015] The control device 10 includes, for example, a control unit 11 and a speed reference setting unit 12. The control unit 11 causes the electric motor 2 to supply electric power according to the result of speed control based on the rotation speed of the electric motor 2 and the speed reference. The speed reference setting unit 12 generates a speed reference for the electric motor 2 in order to control the rotation of the propeller in response to an operation command from the higher-level device 50.

[0016] The control device 10 performs the following control, for example, at the time of startup. The speed reference setting unit 12 generates a speed reference having a magnitude of zero speed or a speed close to zero speed upon receiving an operation command to start operation from the higher-level device 50. At this time, the speed reference setting unit 12 may set the speed reference ω* to a magnitude corresponding to the rotation speed of the motor 2 when the rotation speed (rotation speed ωFB) of the motor 2 detected by the speed sensor 2SS exceeds a first predetermined value, and determine the speed reference ω* based on the result of the judgment as to whether or not the motor 2 can be started. After the start-up, the control unit 11 uses the rotation speed (rotation speed ωFB) of the electric motor 2 detected by the speed sensor 2SS and the speed reference ω* to carry out the speed control of the electric motor 2. The details of the process of generating the speed reference will be described later.

[0017] An example of the start-up process of the embodiment will be described with reference to FIG. 2 and FIG. FIG. 2 is a flowchart of the start-up process according to the embodiment. In the start-up process of the embodiment described below, threshold values ​​ωth1 and ωth2 are used to determine the magnitude of the rotation speed ωFB. For example, the threshold value ωth1 is set to a value greater than the threshold value ωth2. The threshold value ωth2 is set to a value that is not affected by the measurement error contained in the rotation speed ωFB. If the measurement error is estimated to be about 1% of the rated speed, the threshold value ωth2 may be set to, for example, 5% so that it can be detected that the rotation speed ωFB is zero or in the range close to zero. Taking into consideration the magnitude of the threshold value ωth2, the threshold value ωth1 may be set to, for example, 10%. Depending on the magnitude of the threshold value ωth1, the operating state may be set to that magnitude as the speed command ω*. It is advisable to predetermine the magnitude so as not to affect this. If the magnitude of the threshold value ωth1 is expressed as an absolute speed, it would be 1 knot, for example.

[0018] First, the control device 10 judges whether or not a start-up command has been detected (S11). The process of step S11 is repeated at predetermined intervals until a start-up command is detected.

[0019] When the start command is detected, the control device 10 judges whether the rotation speed ωFB is lower than the threshold value ωth2 (S12). When the rotation speed ωFB is lower than the threshold value ωth2, the control device 10 sets the speed command ω* to zero and starts operation (S13), and proceeds to step S18.

[0020] If the rotation speed ωFB is not lower than the threshold value ωth2, the control device 10 judges whether the rotation speed ωFB is lower than the threshold value ωth1 (S14). If the rotation speed ωFB is lower than the threshold value ωth1, the control device 10 designates the most recently detected rotation speed ωFB as the speed command ω* to start operation (S15), and proceeds to step S18. As described above, by setting the most recently detected rotation speed ωFB as the speed command ω*, the magnitude of the speed command ω* does not change suddenly. Since the magnitude of the most recently detected rotation speed ωFB is at a relatively small stage, the above setting switching is performed within the process of automatic control by the control device 10.

[0021] If the rotation speed ωFB is not lower than the threshold value ωth1, the control device 10 checks whether or not to permit the start of operation (S16) and judges the result (S17). If it is judged that the start of operation is permitted, the control device 10 starts operation in the "normal operation mode" according to the set speed command ω* (S18). As described above, even if the most recently detected rotation speed ωFB is set as the speed command ω*, the magnitude of the speed command ω* does not change suddenly, as described above. However, since the most recently detected rotation speed ωFB has become relatively large, the above setting switching is left to the discretion of the user who uses the higher-level device 50.

[0022] When it is determined that the start of operation is not permitted, the control device 10 suspends the start-up (S19). In response to this, the control device 10 may issue a "start-up congestion" or "minor malfunction" report.

[0023] Through the above series of processes, the control device 10 adjusts the start-up process depending on the magnitude of the rotation speed ωFB.

[0024] FIG. 3 is a flowchart of the process of prompting the user to confirm whether or not the operation can be started as shown in FIG.

[0025] The control device 10 outputs a confirmation request to the upper device 50 as to whether or not to execute "speed following start" (S171). For example, the host device 50 receives a confirmation request regarding the execution of this "speed tracking start" and displays it on the display unit. The host device 50 receives a user's response to this confirmation request and notifies the control device 10 of the response result.

[0026] After outputting the confirmation request in step S171, the control device 10 waits until a response is received from the higher-level device 50 (S172).

[0027] When there is a response from the upper level device 50, the control device 10 sets the rotation speed ωFB to the speed command ω* (S173), and reflects the result of the response in a flag (S174).

[0028] The control device 10 may, for example, carry out the above series of processes.

[0029] For example, in order to reduce the shock when starting to operate the ship, the host device 50 may gradually increase the speed reference ω* of the motor 2 from a speed of zero. Even if the ground speed of the ship is zero, if there is a flow velocity in the water around the ship, the propeller and the motor 2 may rotate due to the influence of the flow velocity relative to the ship.

[0030] In the comparative example, when control is performed according to the speed reference ω* of the motor 2 received from the higher-level device 50, power is supplied to the rotating motor 2 such that the motor 2 rotates at zero speed. In such a situation, a shock may occur when starting to operate the ship.

[0031] In this embodiment, the speed reference ω* at the start of operation of the marine vessel is adjusted in the above-described manner to reduce the influence of the flow velocity of the water around the vessel, etc.

[0032] According to the above embodiment, the control device 10 sets the speed reference ω* to a magnitude corresponding to the rotation speed ωFB of the electric motor 2 when the rotation speed ωFB of the electric motor 2 exceeds the first predetermined value ωth1, and controls the speed using the speed reference ω* based on the result of the judgment as to whether or not the electric motor 2 can be started.

[0033] Since the second predetermined value ωth2 is set to a value lower than the first predetermined value ωth1, the rotation speed ωFB of the electric motor 2 may exceed the second predetermined value ωth2 and become lower than the first predetermined value ωth1. In such a case, the control device 10 may set the speed reference ω* to a magnitude corresponding to the rotation speed ωFB of the electric motor 2.

[0034] When the rotation speed ωFB of the electric motor 2 is lower than the second predetermined value ωth2, the control device 10 may set the speed reference ω* to 0 or a predetermined value close to 0. In such a case, even if the speed reference ω* is set to 0 or a predetermined value close to 0, the influence at the time of startup becomes negligible.

[0035] For example, if the propeller connected to the drive device 1 is rotating before operation due to the influence of waves, etc., when an operation is performed to return the rotational speed of the electric motor 2 that drives this propeller to zero, the electric motor 2 will accelerate or decelerate the ship, and the load on the electric motor 2 will temporarily increase. Therefore, before starting operation of the electric motor 2, the most recent rotational speed of the electric motor 2 is set to the initial value of the speed command ω*, and then operation is started, thereby making it possible to start the electric motor 2 while suppressing an increase in the load on the electric motor 2.

[0036] According to at least one of the embodiments described above, the drive device causes the electric motor to drive a propeller of a ship. The drive device includes a power conversion device and a control unit. The power conversion device supplies electric power based on speed control to the electric motor. The control unit supplies electric power to the electric motor according to a result of the speed control based on the rotation speed of the electric motor and a speed reference. The control unit sets the speed reference to a magnitude according to the rotation speed of the electric motor when the rotation speed of the electric motor exceeds a first predetermined value, and determines the speed reference according to a result of a judgment as to whether or not the electric motor can be started, thereby reducing unnecessary electric power supplied to the electric motor when starting the electric motor.

[0037] A part or all of the functional units of the control device 10 in the drive device 1 of the embodiment described above may have a software functional unit that is realized by, for example, executing a program (computer program, software component) stored in a storage unit (memory, etc.) of a computer by a processor (hardware processor) of the computer. Note that a part or all of the functional units of the control device 10 may be realized by hardware such as, for example, an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array), or may be realized by a combination of a software functional unit and hardware.

[0038] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. For example, the configurations of each embodiment may be implemented in combination with each other, and can be applied to components whose descriptions are omitted. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. For example, the above control device 10 is described as including the control unit 11 and the speed reference setting unit 12, but these may be separated into separate control devices. Moreover, the above-mentioned higher-level device 50 may be configured as a computer, or may be configured as a control console in the wheelhouse of the ship. [Explanation of symbols]

[0039] 1...Drive unit 2...Electric motor 10...Control device 11...Control section 12…Speed ​​standard setting section 30...Power conversion device

Claims

1. A drive device for causing an electric motor to drive a propeller of a ship, a power conversion device that supplies power to the electric motor based on the speed control; a control unit that supplies the electric power to the electric motor according to a result of the speed control based on a rotation speed of the electric motor and a speed reference; a speed reference setting unit for generating the speed reference; Equipped with The speed reference setting unit When the rotation speed of the electric motor exceeds a first predetermined value, the speed reference is set to a value corresponding to the rotation speed of the electric motor, The speed reference is determined according to a result of determining whether the motor is started or not. Drive device.

2. The second predetermined value is set to a value lower than the first predetermined value, The speed reference setting unit When the rotation speed of the electric motor exceeds the second predetermined value and is lower than the first predetermined value, the speed reference is set to a value corresponding to the rotation speed of the electric motor.

2. The drive device according to claim 1.

3. The speed reference setting unit The speed reference is set to 0 or a predetermined value close to 0 when the rotation speed of the electric motor is lower than the second predetermined value.

3. The drive device according to claim 2.

4. A method for controlling a drive device that causes an electric motor to drive a propeller of a ship, comprising the steps of: The drive device is a power conversion device that supplies power to the electric motor based on the speed control; a control unit that supplies the electric power to the electric motor according to a result of the speed control based on a rotation speed of the electric motor and a speed reference; Equipped with When the rotation speed of the electric motor exceeds a first predetermined value, the speed reference is set to a value corresponding to the rotation speed of the electric motor, The speed reference is determined according to a result of determining whether the motor is started or not. Control methods.

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