JP2011251595A - Apparatus and method for driving electric propulsion ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for driving an electric propulsion ship that controls stop by a simple method without abruptly changing a voltage of a power bus of an inboard power supply.SOLUTION: The apparatus for driving an electric propulsion ship includes a motor 1 connected to a shaft of a propeller P for ship propulsion, an electric converter 2 to be supplied with power from an inboard power supply 3 to drive the motor 1, and a controller 4 for controlling the electric converter 2. The controller 4 includes a speed controller 41 that controls a speed on the basis of an external speed command to output a torque reference, and an operation sequence control unit 46 that controls operation stop of the motor 1 on the basis of an external operation command. The operation sequence control unit 46 temporarily reduces a speed reference at a predetermined speed-reduction rate when the external operation command is off, and stops the electric converter 2 to shut off a current when the torque reference becomes less than a predetermined value or it changes from power running to regeneration.

Description

  The present invention relates to a drive device and a drive method for an electric propulsion ship that drives a propeller for propulsion with an electric motor.

  2. Description of the Related Art A drive device for an electric propulsion ship in which a ship propulsion propeller is driven by an electric motor controlled using a power conversion apparatus to propel the ship is well known.

  A stop command is given to such an electric propulsion ship, and there are several ways to perform stop control. For example, proposals have been made to shorten braking time by combining electrical braking means and reverse braking (see, for example, Patent Document 1).

JP 2007-125909 A (Overall)

  The technique disclosed in Patent Document 1 performs electrical braking in a region where the motor speed is high, and performs reverse-phase braking when the speed falls below a predetermined value. A device such as a resistor that consumes power is required, and the control device is complicated.

  On the other hand, when a stop command is given to the electric propulsion ship, there is a so-called free run stop by turning off the operation of the electric motor by the power converter. When the power converter is stopped and the current is cut off, the speed of the motor decreases according to a predetermined deceleration curve due to the load torque of the propeller for propulsion. For example, if the electric propulsion vessel is small and does not require a rapid stop, this free-run deceleration without the need for additional equipment is sufficient.

  However, when the input current to the power converter suddenly decreases at the start of free-run deceleration and the power supply capacity of the inboard power supply is small, the voltage of the power supply bus of the inboard power supply rises rapidly or suddenly changes to control it. There is a problem of doing. Since the inboard load is connected to the power supply bus, if the fluctuation of the power supply voltage is large, there is a risk of malfunction or damage of the inboard load equipment. If the shipboard load has a voltage type inverter, for example, charging / discharging of the smoothing capacitor of the voltage type inverter input section may cause overcurrent detection malfunction or fuse blown.

  The present invention has been made to solve the above-described problems, and is a drive device for an electric propulsion ship capable of performing stop control in a simple manner without causing a sudden change in the voltage of the power bus of the ship power supply. It is another object of the present invention to provide a driving method.

  In order to achieve the above object, a drive device for an electric propulsion ship according to the present invention includes an electric motor connected to a shaft of a propeller for propulsion of a ship, a power conversion device that is fed from an onboard power source and drives the electric motor, and the electric power A control device that controls the conversion device, the control device speed-controlling based on an external speed command and outputting a torque reference, and an electric motor based on an external operation command An operation sequence control unit for controlling operation stop, and when the operation command from the outside is turned off, the operation sequence control unit temporarily decelerates the speed reference at a predetermined deceleration rate, and the torque reference is a predetermined value. The power conversion device is stopped and the current is cut off when the power consumption changes from the power running to the regeneration.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the drive device and drive method of an electric propulsion ship which can perform stop control by a simple method, without making the voltage of the power supply bus line of an inboard power supply suddenly change.

The circuit block diagram of the drive device of the electric propulsion ship which concerns on Example 1 of this invention. 3 is a flowchart of stop control according to the first embodiment. 3 is a time chart of a stop control operation in the first embodiment. The circuit block diagram of the inverter control part of the drive device of the electric propulsion ship which concerns on Example 2 of this invention. 10 is a flowchart of stop control according to the second embodiment. 6 is a time chart of a stop control operation in the second embodiment. The main circuit block diagram of the drive device of the electric propulsion ship which concerns on Example 3 of this invention. The main circuit block diagram of the drive device of the electric propulsion ship which concerns on Example 4 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  Hereinafter, a driving device and a driving method for an electric propulsion ship according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a circuit configuration diagram of a drive device for an electric propulsion ship according to a first embodiment of the present invention. As shown in FIG. 1A, the inboard power supply 3 is connected to the power converter 2 and the inboard load 6 through the power bus 5. The inboard power supply 3 includes an AC generator 31. The power conversion device 2 includes an input transformer 21, a converter 22 that converts the secondary voltage of the input transformer 21 into direct current, a capacitor 23 that smoothes the direct current output of the converter 22, and the direct current output of the converter 22 into alternating current output. And an inverter 24 for conversion.

  The inverter 24 is given a drive signal from the control unit 4. Specifically, this drive signal is an on / off signal applied to the gates of the switching elements constituting the inverter 24. The three-phase output of the inverter 24 is connected to the AC motor 1, and the AC motor 1 drives the propulsion propeller P. A current detector 7 is provided on the output side of the inverter 24, and a current signal detected thereby is given to the control unit 4. Further, the AC motor 1 is provided with a speed detector 8, and a speed signal detected thereby is also given to the control unit 4.

  FIG. 1B shows the internal configuration of the control unit 4. The speed command given from the outside is given to the speed control unit 41 via a rate reducer 47 whose details will be described later. The speed control unit 41 is given a speed FB obtained by converting the speed signal detected by the speed detector 8 into an appropriate signal by the speed detection unit 42. The speed control unit 41 performs control so that the deviation between the speed command and the speed FB is minimized, and outputs a torque reference. This torque reference is given to the current control unit 43. The current control unit 43 is supplied with a current FB obtained by converting the current signal detected by the current detector 7 into an appropriate signal by the current detection unit 44. The current control unit 43 outputs a voltage reference by controlling the deviation between the torque reference and the current FB to be a minimum. This voltage reference is given to the drive signal generator 45. The drive signal generator 45 gives a drive signal to the switching elements constituting the inverter 24 so that the output voltage of the inverter 24 becomes the voltage reference.

  The operation sequence control unit 46 gives an operation signal to the drive signal generation unit 45 based on the operation command of the electric motor given from the outside. The operation sequence control unit 46 outputs a rate deceleration command to the rate reducer 47 when the operation command is turned off and becomes a stop command. In this state, the time when the torque reference, which is the output of the speed control unit 41, changes from powering to regeneration is detected by the powering regeneration detector 48, and a stop signal is given to the drive signal generator 45 for the first time.

  The operation at the time of stop control in the above configuration will be described below with reference to FIGS.

  FIG. 2 is a flowchart at the time of stop control of the operation sequence control unit 46. First, it is determined whether or not the operation command has become 0, that is, whether or not a stop command has been given (ST1). If the operation command is 0, the speed reference is rate-decelerated (ST2). Next, it is determined whether the torque reference is 0 or negative (ST3). When the torque reference becomes 0 or negative, the operation signal is set to 0 and a stop signal is given to the drive signal generator 45.

  FIG. 3 shows the operation of the stop control in a time chart. While the motor is operating at the speed SP1, the operation command is turned off at time t = t1. Then, the speed command decreases from SP1 at a predetermined rate, and the speed of the motor is also reduced at the same rate. It is important to set the predetermined rate to a gentler slope than the deceleration rate of the deceleration curve by free run at the speed SP1 as shown in the figure. In this way, the change in torque reference at time t = t1 is smaller than the change during free run. Therefore, voltage fluctuations applied to the power supply bus 5 are reduced.

  Since the load torque of the propeller P for propulsion is approximately proportional to the square of the rotational speed, power running is performed in the high speed region up to time t = t2, but switching to regenerative operation is performed when the speed is reduced to the speed at time t = t2. At time t = t2 when switching from the power running operation to the regenerative operation, the AC motor 1 is free-run stopped. Since the torque reference during power running is positive and the torque reference during regenerative operation is negative, the timing for switching from power running to regenerative operation is judged by the power running regenerative detector 48 based on the polarity of the torque reference, and the operation signal is turned off. To do. Since the output of the AC motor 1 is 0 at time t = t2, the load of the inboard power supply 3 does not change and the voltage of the power supply bus 5 does not fluctuate if the power conversion device 2 is stopped and the current is cut off at this timing.

  As apparent from the above description, the rate reducer 47 performs rate deceleration only when a rate deceleration command is given from the operation sequence control unit 46, and otherwise bypasses input and output. In addition, although it has been described that the power running regeneration detector 48 detects the polarity of the torque reference, it may be detected that the torque reference is equal to or less than a predetermined value.

  An electric propulsion ship driving apparatus and driving method according to Embodiment 2 of the present invention will be described below with reference to FIGS.

  FIG. 4 is an internal configuration diagram of the control unit of the drive device for the electric propulsion ship according to the second embodiment of the present invention. The same parts as those of the control unit of the drive unit for the electric propulsion ship according to the first embodiment of the present invention shown in FIG. The second embodiment is different from the first embodiment in that a rate changer 49 is provided and the deceleration rate of the rate reducer 47A is changed according to the value of the speed FB.

  The operation at the time of stop control in the above configuration will be described below with reference to FIGS.

  FIG. 5 is a flowchart at the time of stop control of the operation sequence control unit 46A. The same parts of the flowchart of the second embodiment as those of the flowchart of the stop control of the operation sequence control unit 46 according to the first embodiment of the present invention shown in FIG. The difference of the second embodiment from the first embodiment is that it is determined whether or not the speed reference is decelerated to a predetermined speed after decelerating the speed reference in step ST2 (ST2A). Is changed (ST3A).

  FIG. 6 shows the above stop control operation in a time chart. The difference from the time chart of FIG. 3 in the first embodiment is that the deceleration rate when the operation command becomes 0 at time t = t1 is set more gently than the gradient in the first embodiment, and the rate changer at time t = t3. 49 is a point that when the predetermined speed SP2 is detected, the gradient of the deceleration rate is changed to a steep gradient.

  According to the second embodiment, it is possible to suppress the torque reference fluctuation in the high speed region (time t = t1) as compared with the first embodiment, so that the voltage fluctuation applied to the power supply bus 5 is reduced. It is obvious that the influence of the torque reference variation on the voltage variation of the power supply bus 5 is small in the low speed region. In the present embodiment, the deceleration rate is changed once. However, it is needless to say that finer variations can be suppressed if the deceleration rate is changed a plurality of times.

  In the second embodiment, the deceleration rate is changed according to the decrease in the speed of the AC motor 1. However, the deceleration rate may be changed according to the setting of the timer instead of the decrease in the speed. .

  FIG. 7 is a main circuit configuration diagram of the drive device for the electric propulsion ship according to the third embodiment of the present invention. In the third embodiment, the same parts as those in the main circuit configuration diagram of the drive device for an electric propulsion ship according to the first embodiment of the present invention shown in FIG. The difference between the third embodiment and the first embodiment is that the converter of the power conversion device 2A is a diode converter 21A.

  Since the diode converter 21A cannot perform a regenerative operation, when the AC motor 1 is in a regenerative operation, the DC voltage of the smoothing capacitor 23 may rise and damage a device such as a smoothing capacitor. Therefore, it is necessary to take measures such as adding a resistance braking circuit so that the DC voltage value does not rise above a certain level.

  However, as in the first embodiment, when the operation command is turned off, the speed of the AC motor 1 is once decelerated at a constant rate, and the timing at which the torque reference is switched from power running to regeneration, or the torque reference is below a predetermined value. If the power conversion device is stopped at this timing, the regenerative operation is not performed, and thus a countermeasure such as a resistance braking circuit becomes unnecessary.

  FIG. 8 is a main circuit configuration diagram of the drive device for the electric propulsion ship according to the fourth embodiment of the present invention. The same parts as those in the main circuit configuration diagram of the drive unit for the electric propulsion ship according to the first embodiment of the present invention shown in FIG. 1A are denoted by the same reference numerals and the description thereof will be omitted. The third embodiment is different from the first embodiment in that the ship power supply 3 is a DC power supply 32, the power supply bus 5A is a DC circuit, and the input transformer 21 and the converter 22 of the power converter 2B are omitted. This is the point where the inboard load 6A is a DC power supply type.

  In the case of the fourth embodiment, when the AC motor 1 is in a regenerative operation, the DC voltage of the power supply bus 5 is increased, so that there is a possibility that the equipment of the inboard load 6 malfunctions. Therefore, as in the first embodiment, when the operation command is turned off, the speed of the AC motor 1 is once decelerated at a constant rate, and the power converter 2B is stopped at the timing when the torque reference is switched from power running to regeneration. In this case, since the regenerative operation is not performed, malfunction of the inboard load 6A can be prevented. Thus, even if the power supply bus 5 is a DC circuit, this method can be applied.

  In the above description, it is apparent that the present invention is effective even if the AC motor 1 is replaced with a DC motor. In this case, a DC Leonard device or a DC chopper device may be used as the power conversion device 2.

DESCRIPTION OF SYMBOLS 1 AC motor 2, 2A, 2B Power converter 3 Inboard power supply 4, 4A Control device 5, 5A Power supply bus 6, 6A Inboard load 7 Current detector 8 Speed detector 21 Input transformer 22 Converter 22A Diode converter 23 Capacitor 24 Inverter 31 AC generator 32 DC power supply 41 Speed control unit 42 Speed detection unit 43 Current control unit 44 Current detection unit 45 Drive signal generation unit 46 Operation sequence control unit 47, 47A Rate reducer 48 Power running detector 49 Rate changer

Claims (6)

An electric motor connected to the shaft of the propeller for ship propulsion,
A power converter that is fed from an onboard power source and drives the motor;
A control device for controlling the power converter,
The control device includes a speed control unit that controls a speed based on an external speed command and outputs a torque reference, and an operation sequence control unit that controls an operation stop of the motor based on an external operation command. ,
The operation sequence controller is
When the external operation command is turned off, the speed reference is once decelerated at a predetermined deceleration rate, and the power converter is stopped when the torque reference falls below a predetermined value or changes from power running to regeneration. The electric propulsion ship drive device is characterized in that the current is cut off.   2. The electric propulsion ship drive device according to claim 1, wherein the predetermined deceleration rate is a linear deceleration rate with respect to time.   The drive device for an electric propulsion ship according to claim 1, wherein a deceleration rate of the predetermined deceleration rate is changed in accordance with a speed of the electric motor. An electric motor connected to the shaft of the propeller for ship propulsion,
A power converter that is fed from an onboard power source and drives the motor;
A control device for controlling the power converter,
The control device includes a speed control unit that outputs a torque reference by controlling speed based on an external speed command, and an operation sequence control unit that controls operation stop of the electric motor based on an external operation command. In the propulsion ship drive,
When the external operation command is turned off, the speed reference is once decelerated at a predetermined deceleration rate, and the power converter is stopped when the torque reference falls below a predetermined value or changes from power running to regeneration. An electric propulsion ship driving method characterized in that the electric current is cut off.   5. The electric propulsion ship driving method according to claim 4, wherein the predetermined deceleration rate is a linear deceleration rate with respect to time.   5. The electric propulsion ship driving method according to claim 4, wherein a deceleration rate of the predetermined deceleration rate is changed in accordance with a speed of the electric motor.

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