JP2013059171A - Power transmission device and power transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device that has a voltage regulation function of keeping a substantially constant DC voltage generated in the process of power transmission and output externally.SOLUTION: A power transmission device 1 having power generation means 4 disposed on a driving rotary shaft 2 to generate an alternating current with rotation of the driving rotary shaft 2, an inverter 6 for rectifying the alternating current generated by the power generation means 4 once to a direct current, and then outputting a frequency conversion thereof, and motor means 5 for receiving the alternating current from the inverter 6 to generate a rotative driving force on a follower rotary shaft 3 includes: a DC supply section capable of externally outputting the direct current in the inverter 6; a voltage measurement section 8 for measuring a DC voltage in the inverter 6; and a frequency adjustment section 10 for changing the conversion frequency in the inverter 6 such that the value measured by the voltage measurement section 8 remains constant.

Description

  The present invention relates to a power transmission device and a power transmission method for transmitting rotational power of a drive rotary shaft to a driven rotary shaft that is not connected to the drive rotary shaft.

As a means for transmitting the rotational power of a drive rotary shaft driven by a turbine or the like to a driven rotary shaft, there is a power device including a shaft coupling and a gear mechanism. In addition, an electric power transmission device provided with such a power device has been developed.
For example, Patent Document 1 discloses that “a rotating electrical machine connected to a turbine and an engine are connected via a rotational transmission mechanism having a clutch, and the clutch is opened and the rotating electrical machine is generated only by the rotational force of the turbine. In addition to the driving state, the clutch is engaged to assist the power generation drive of the rotating electrical machine by the output of the engine, or the state in which the rotational force of the turbine is added to the driving force of the engine is controlled according to the operating state. An apparatus is disclosed. Further, this power device is provided with an electric power transmission device that operates a drive motor or the like with the electric power generated by the rotating electrical machine.

  Specifically, the power transmission device disclosed in Patent Document 1 is configured to be able to output electric power generated by a generator provided on a drive rotary shaft extending from a turbine to the outside via an inverter. The output electric power can be supplied to the battery, and the drive motor or the like is operated by the electric power from the battery.

JP 2000-345915 A

  However, in the technique of Patent Document 1, if the rotational speed of the turbine fluctuates, or if the rotational force of the turbine is not used as engine auxiliary power by operating the clutch, the rotational speed of the rotating electrical machine varies. The DC output voltage from the inverter to the battery may become unstable. For this reason, it is difficult to always extract the DC output to the battery at a constant voltage in a normal power generation state in which electric power is generated by rotating the rotating electrical machine with the rotational force of the turbine.

  The present invention has been made in view of the above-described problems, and provides a power transmission device capable of always taking out a DC output to a battery or the like at a constant voltage by suppressing a load fluctuation of a DC part of an inverter. With the goal.

In order to achieve the object, the present invention takes the following technical means.
That is, the power transmission device of the present invention includes an electromotive means that is provided on a drive rotary shaft and generates alternating current by the rotation of the drive rotary shaft, and frequency conversion after the alternating current generated by the electromotive means is once rectified to direct current. And a motor means for generating a rotational driving force on the driven rotating shaft when AC is input from the inverter, and a DC supply capable of outputting DC in the inverter to the outside A voltage measuring unit that measures a DC voltage in the inverter, and a frequency adjusting unit that varies a conversion frequency in the inverter unit so that a measurement value of the voltage measuring unit is constant. It is characterized by being.

Preferably, the DC supply unit may be further capable of inputting a direct current from an external power source.
Preferably, the electromotive means includes a magnet provided at one end of the drive rotary shaft and a stator winding capable of generating an alternating current by a rotating magnetic field generated by the magnet as the drive rotary shaft rotates. It is good to have.

Preferably, the motor means includes a stator winding that generates a magnetic field by alternating current input from the inverter, and a magnet that is provided at one end of the driven rotating shaft and rotates by the magnetic field generated by the stator winding. It is good to have.
On the other hand, in the power transmission method of the present invention, alternating current is generated by the rotation of the drive rotation shaft, the generated alternating current is once rectified to direct current by an inverter, frequency is converted, and the driven rotational shaft is rotationally driven by the frequency converted alternating current. In the power transmission method for transmitting the rotational driving force of the driving rotating shaft to the driven rotating shaft by generating a force, the DC voltage is measured, and the frequency conversion is performed so that the measured DC voltage is constant. In this case, the frequency is variable.

  According to the power transmission device and the power transmission method of the present invention, the DC power generated during the power transmission is stably supplied to the outside while maintaining the constant voltage while transmitting the rotational power of the driving rotary shaft to the driven rotary shaft. It becomes possible to do.

It is the figure which showed the outline of the power transmission device. It is the figure which showed the binary electric power generation system with which the power transmission device of this invention was used.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the power transmission device 1 of the present invention is provided between a drive rotary shaft 2 and a driven rotary shaft 3 that is not directly connected to the drive rotary shaft 2. Is transmitted to the driven rotating shaft 3.
Conventionally, as a device for transmitting rotational power, there is a mechanical device composed of a shaft coupling, a gear mechanism, etc., but the power transmission device 1 of the present embodiment once converts rotational power into electrical energy, An electric system that uses this electric energy to transmit power is adopted.

That is, the power transmission device 1 of the present invention includes an electromotive means 4 that generates an alternating current by the rotation of the drive rotary shaft 2, an inverter 6 that converts the alternating current into a direct current and converts the frequency again into an alternating current, And motor means 5 for generating a rotational driving force on the driven rotary shaft 3 by the alternating current subjected to frequency conversion.
The inverter 6 provided in the power transmission device 1 is provided with a DC supply unit 7 that can output this DC voltage to the outside when the AC input from the electromotive means 4 is once rectified to DC. .

Furthermore, the power transmission device 1 has a voltage measurement unit 8 that measures the DC voltage rectified by the inverter 6 and a conversion frequency for the frequency conversion unit 9 so that the measurement value of the voltage measurement unit 8 is constant. And a frequency adjusting unit 10 that emits a signal that changes the frequency.
Hereinafter, details of the electromotive means 4, the inverter 6, the motor means 5, the voltage measuring unit 8, and the frequency adjusting unit 10 will be described.

As shown in FIG. 1, the electromotive means 4 includes a magnet (permanent magnet in the present embodiment) 11 provided at the distal end portion of the drive rotating shaft 2 and a fixed arranged so as to correspond to the permanent magnet 11. It is comprised with the child winding 12.
A plurality of permanent magnets 11 are arranged so as to be embedded in the outer peripheral surface on the distal end side of the drive rotating shaft 2.

A driven rotary shaft 3 is arranged coaxially in front of the front end of the drive rotary shaft 2 (to the right in FIG. 1). In this embodiment, the drive rotary shaft 2 and the driven rotary shaft 3 are separated by a partition wall 13. It is isolated. Note that the drive rotary shaft 2 and the driven rotary shaft 3 do not necessarily have to be arranged coaxially, and may be installed in different axes where the axes do not coincide with each other.
The partition wall 13 is provided with an annular protrusion 14 for accommodating the stator winding 12. The annular projecting portion 14 is provided so as to project from the partition wall 13 toward the base end side of the drive rotating shaft 2, and has an annular shape in a front view from the drive rotating shaft 2 side. A stator winding 12 is attached to the annular protrusion 14.

That is, the stator winding 12 is formed by winding a conducting wire around a core body such as an iron core in a coil shape, and a plurality of stator windings 12 are arranged along the inner peripheral surface of the annular protrusion 14 at equal intervals in the circumferential direction. ing. The number of stator windings 12 is preferably three or two, and may be a multiple of 3 or a multiple of 2. In the case of the present embodiment, the number of stator windings 12 is three, and the electromotive means 4 can generate a three-phase alternating current.

The drive rotary shaft 2 is rotatably disposed at the center of the annular protrusion 14 and is inserted into the annular protrusion 14 so that the stator winding 12 and the permanent magnet 11 face each other in the radial direction.
As shown in FIG. 1, when the plurality of permanent magnets 11 embedded on the front end side of the drive rotary shaft 2 rotate around the axis of the drive rotary shaft 2 as the drive rotary shaft 2 rotates, A rotating magnetic field is generated around it. The generated rotating magnetic field generates an alternating current (three-phase alternating current) in the stator winding 12 disposed in the annular protrusion 14. The generated three-phase alternating current is input to the inverter 6.

The inverter 6 frequency-converts the three-phase alternating current input from the electromotive means 4 and outputs it as a three-phase alternating current having different frequencies.
Specifically, the inverter 6 includes a rectifier 15 that once converts alternating current input from the electromotive means 4 into direct current, and a frequency converter 9 that generates three-phase alternating current obtained by converting the frequency again from the direct current. And is composed of. Furthermore, the inverter 6 is provided with a DC supply unit 7 (in this embodiment, a DC output terminal) that can output the direct current converted by the rectifying unit 15 to the outside.

The rectifying unit 15 includes three wires connected in series with two diodes 16 in parallel, and these wires are connected in parallel. Any of the three-phase AC wirings is connected between the diodes 16 in the respective wirings. A smoothing capacitor 17 arranged in parallel with the parallel wiring to which the diode 16 is connected is connected.
The alternating current input from the electromotive means 4 to the inverter 6 is converted (rectified) into direct current by the diode 16 of the rectifier 15, and the converted direct current is smoothed by the smoothing capacitor 17.

The frequency conversion unit 9 is configured by a semiconductor switching element 18 such as an IGBT (Insulated Gate Bipolar Transistor).
Specifically, the frequency conversion unit 9 arranges two semiconductor switching elements 18 in series, and connects the collector of one semiconductor switching element 18 and the emitter of the other semiconductor switching element 18, and these wirings are connected in parallel. Three wires are provided, and these wires are connected in parallel. With respect to each wiring in which two semiconductor switching elements 18 are connected in series, the output of the inverter 6 is taken out from the position between the two semiconductor switching elements 18.

The direct current converted by the rectifier 15 is switched by the semiconductor switching element 18 so that it can be output as an alternating current (three-phase alternating current) having a desired frequency.
The output three-phase alternating current is input to the motor means 5 provided at the tip of the driven rotary shaft 3 and converted into the rotational driving force of the driven rotary shaft 3.
As shown in FIG. 1, the motor unit 5 has substantially the same configuration as the electromotive unit 4, and is arranged so as to correspond to the magnet (permanent magnet in the present embodiment) 11 and the permanent magnet 11. It consists of a stator winding 12.

A plurality of permanent magnets 11 are arranged so as to be embedded in the outer peripheral surface on the distal end side of the driven rotary shaft 3.
Similar to the electromotive means 4, the partition wall 13 is provided with an annular protrusion 14 that protrudes toward the proximal end of the driven rotary shaft 3, and the stator winding 12 is provided on the annular protrusion 14. Is attached. The stator winding 12 is formed by winding a conducting wire around a core body such as an iron core in a coil shape, and a plurality of stator windings 12 are arranged along the inner peripheral surface of the annular protrusion 14 at equal intervals in the circumferential direction. . The number of stator windings 12 is preferably three or two, and may be a multiple of 3 or a multiple of 2. In the present embodiment, the number of stator windings 12 is three.

The driven rotary shaft 3 is disposed coaxially with the annular protrusion 14 and is rotatably inserted into the annular protrusion 14 so that the stator winding 12 and the permanent magnet 11 face each other in the radial direction. Yes.
As shown in FIG. 1, the three-phase alternating current frequency-converted by the inverter 6 is input to the stator winding 12 in the motor means 5. The stator winding 12 generates a magnetic field by the inputted three-phase alternating current. The plurality of permanent magnets 11 embedded on the distal end side of the driven rotary shaft 3 repel each other against the generated magnetic field, so that the driven rotary shaft 3 rotates.

In the motor means 5, the permanent magnet 11 disposed on the distal end side of the driven rotary shaft 3 can be an induction coil (winding type or saddle type).
The driven rotary shaft 3 to which the rotational power of the drive rotary shaft 2 has been transmitted drives the load ahead. As the load, various types such as a pump, a generator, a mechanism for winding up a weight like an elevator, and a driving means for a crane can be used. Further, the motor means 5 can be suitably used as an auxiliary power source for other rotational drive means (motor or the like) for rotationally driving the load.

  By the way, the inverter 6 provided in the power transmission device 1 of the present invention includes a DC supply unit 7 that can output the DC voltage converted by the rectification unit 15 to the outside. Specifically, the DC supply unit 7 includes a direct current output terminal (DC supply terminal). The direct-current power output from the DC supply unit 7 can contribute to charging the battery and supplying power to the main drive unit and auxiliary drive unit (auxiliary machine) of the drive system provided outside. Since the DC power output is stable, the DC supply unit 7 does not simply store surplus power temporarily with respect to the fixedly connected battery, but with respect to the detachably connected battery. Thus, it can be particularly suitably used as a charger for charging.

The DC supply unit 7 is a very useful “power supply unit”. However, when the external device connected to the inverter, the load of the device, etc. fluctuate, the DC voltage output from the DC supply unit 7 However, there was a drawback that it was likely to become unstable.
Therefore, the power transmission device 1 of the present embodiment includes a voltage measuring unit 8 that measures the DC voltage converted by the rectifying unit 15 of the inverter 6 in order to make the DC output voltage constant, and the voltage measuring unit. A frequency adjusting unit 10 that adjusts to a necessary frequency is provided so that the measured value measured in 8 is constant.

The voltage measuring unit 8 that measures the voltage of the DC supply unit 7 can use a known voltmeter, a voltage measuring unit of a sequencer, or the like. The measured DC voltage value in the inverter 6 is output to the frequency adjusting unit 10. Is done.
The frequency adjustment unit 10 compares the voltage value measured by the voltage measurement unit 8 with a preset voltage value, and adjusts the frequency conversion unit 9 in the inverter 6 to match the set voltage value. A switching signal is generated. This switching signal is input to the gate of the semiconductor switching element 18 and the switching frequency of the frequency converter 9 is changed.

For example, when the voltage value measured by the voltage measurement unit 8 is lower than a preset voltage value, the frequency adjustment unit 10 increases the switching frequency of the frequency conversion unit 9 and is measured by the voltage measurement unit 8. When the voltage value exceeds a preset voltage value, the frequency adjustment unit 10 decreases the switching frequency of the frequency conversion unit 9.
Next, the operation mode of the power transmission device 1 will be described.

In describing the operation mode, an example in which the power transmission device 1 of the present embodiment is applied to the binary power generation system 19 will be described, and the description will proceed. In addition, it cannot be overemphasized that the power transmission device 1 of this embodiment is applicable to power transmission with various rotating shafts.
As shown in FIG. 2, the binary power generation system 19 is driven to rotate by evaporating the working medium vaporized by the evaporator 20 by using heat from an external heat source and expanding the vapor of the working medium evaporated by the evaporator 20. An expander 21 that generates force, a condenser 22 that condenses the vapor of the working medium expanded by the expander 21 into a liquid, and a working medium pump that circulates the working medium of the liquid condensed by the condenser 22 23 (auxiliary machine) is provided on a closed loop circulation pipe. Furthermore, it has the generator 24 which produces electric power with the rotational drive force which arose in the expander 21. The rotation shaft (drive rotation shaft 2) of the expander 21 and the rotation shaft (driven rotation shaft 3) of the generator 24 are connected by the power transmission device 1.

  When generating power with the binary power generation facility, first, the liquid working medium is vaporized into vapor by the evaporator 20. The vapor of the working medium is sent to the expander 21 and expands in the expander 21 to rotate the screw rotor. The vapor of the working medium that has rotated the screw rotor is sent to the condenser 22 and returns to the liquid again. The working medium that has become liquid in the condenser 22 is sent again to the evaporator 20 using the working medium pump 23 and used for evaporation. The rotating machine power of the screw rotor in the expander 21 is transmitted to the generator 24 via the power transmission device 1 to generate power.

  During power generation, when the drive rotary shaft 2 of the expander 21 rotates, the electromotive means 4 provided at the tip of the drive rotary shaft 2, that is, a plurality of permanent magnets 11 embedded on the tip end side of the drive rotary shaft 2 are provided. It rotates around the axis of the drive rotary shaft 2 and a rotating magnetic field is generated around the drive rotary shaft 2 of the electromotive means 4. The rotating magnetic field generated in this way causes an alternating current (three-phase alternating current) to be generated in the stator winding 12 disposed on the annular protrusion 14 of the electromotive means 4, and the generated three-phase alternating current is the inverter 6. Is input. In other words, the electromotive means 4 operates as a generator 24 that generates three-phase AC power using the rotation of the drive rotary shaft 2 and sends the generated three-phase AC current to the inverter 6.

  The three-phase AC current sent to the inverter 6 is first input to the rectifier 15 of the inverter 6. In the rectifier 15, the three-phase alternating current is converted (rectified) into direct current by the action of two diodes 16 connected in series. The direct current thus converted is smoothed by the smoothing capacitor 17 and then sent to the frequency converter 9. On the other hand, a DC supply unit 7 is provided at a portion of the smoothing capacitor 17 that is converted (rectified) into a direct current, and a voltage measuring unit that measures the direct-current voltage converted by the rectifying unit 15. 8 is provided. Further, the DC voltage measured by the voltage measuring unit 8 is output to the frequency adjusting unit 10.

  In the frequency adjustment unit 10, a switching signal is output to the frequency conversion unit 9 so that the voltage value measured by the voltage measurement unit 8, that is, the output of the DC supply unit 7 becomes a preset voltage value. In the frequency converter 9, this switching signal is input to a semiconductor switching element 18 such as an IGBT, and a direct current is switched at a desired frequency and output to the motor means 5 as a three-phase alternating current. In the motor means 5, the input three-phase alternating current is converted into the rotational driving force of the driven rotary shaft 3 of the generator 24.

  In this way, in the power transmission device 1 of the present invention, the rotational driving force of the expander 21 is once converted into electric energy, transmitted to the driven rotating shaft 3 side via the inverter 6, and converted into the rotational driving force again. Thus, the rotational driving force of the drive rotary shaft 2 can be reliably transmitted to the driven rotary shaft 3. At this time, by changing the frequency of the switching signal of the frequency converter 9, the rotational speed of the driven rotary shaft 3 can be increased or decreased. That is, the power transmission device 1 can be used as a speed increaser or a speed reducer. If this function is used, in the power transmission device 1 of the present invention, for example, when the rotation speed of the drive rotating shaft 2 fluctuates and the voltage of the DC section fluctuates, the rotation speed in the frequency conversion section 9 is increased. The DC voltage can be maintained almost constant by speeding up or slowing down.

  Further, as shown in FIG. 2, the DC voltage converted by the rectifying unit 15 using the DC supply unit 7 of the inverter 6 can be output to the outside. The direct-current power output from the DC supply unit 7 in this way may be used to supply power to an auxiliary machine such as the working medium pump 23 or a drive unit of a drive system provided outside. However, the present invention is not limited to this, and may be used for power supply for charging a battery that is detachably connected to the DC supply unit 7. That is, you may use DC supply part 7 of power transmission device 1 as a battery charger. Thus, when the DC voltage is output from the DC supply unit 7 to the outside, the frequency of the switching signal output from the frequency conversion unit 9 is set so that the DC voltage measured by the voltage measurement unit 8 becomes a constant value. It is good to raise and lower within an allowable range. As a result, it is possible to improve the DC voltage quality output to the auxiliary machine, the battery, and the like.

  As described above, the power transmission device 1 stably supplies the direct current generated during the power transmission to the outside while maintaining the constant voltage while transmitting the rotational power of the drive rotating shaft to the driven rotating shaft. Can do. Further, when power is transmitted between the drive rotary shaft 2 and the driven rotary shaft 3 in the power transmission device 1, the DC power output from the power transmission device 1 is used for an auxiliary machine or the like of the binary power generation system 19. Thus, the efficiency of the power generation system can be improved as a whole apparatus.

The DC supply unit 7 may be capable of inputting a direct current from an external power source. In this way, since the DC power can be supplied from the outside via the DC supply unit 7 while the power generation is stabilized at the time of starting the binary power generation system 19, the start-up can be performed smoothly.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Drive rotary shaft 3 Driven rotary shaft 4 Electromotive means 5 Motor means 6 Inverter 7 DC supply part 8 Voltage measurement part 9 Frequency conversion part 10 Frequency adjustment part 11 Permanent magnet 12 Stator winding 13 Bulkhead 14 Ring protrusion 15 rectifier 16 diode 17 smoothing capacitor 18 semiconductor switching element 19 binary power generation system 20 evaporator 21 expander 22 condenser 23 working medium pump 24 generator

Claims (5)

An electromotive means for generating an alternating current by rotation of the drive rotating shaft provided on the drive rotary shaft; an inverter that rectifies the alternating current generated by the electromotive means into a direct current and then outputs a frequency conversion; and And a motor means for generating a rotational driving force on the driven rotary shaft when the alternating current is input,
A DC supply unit capable of outputting the direct current in the inverter to the outside;
A voltage measurement unit that measures a DC voltage in the inverter, and a frequency adjustment unit that varies a conversion frequency in the inverter so that a measurement value of the voltage measurement unit is constant. Power transmission device.   The power transmission device according to claim 1, wherein the DC supply unit can further receive a direct current from an external power source. The electromotive means includes
A magnet provided at one end of the drive rotating shaft;
A stator winding capable of generating an alternating current by a rotating magnetic field generated by the magnet as the drive rotation shaft rotates;
The power transmission device according to claim 1, wherein the power transmission device is provided. The motor means includes
A stator winding that generates a magnetic field by alternating current input from the inverter;
A magnet that is provided at one end of the driven rotating shaft and rotates the driven rotating shaft by a magnetic field generated by a stator winding;
The power transmission device according to claim 1, wherein the power transmission device is provided. AC is generated by rotation of the drive rotary shaft, and the generated AC is once rectified to direct current by an inverter, then frequency-converted, and a rotational drive force is generated in the driven rotary shaft by the frequency-converted alternating current. In the power transmission method of transmitting the rotational driving force of
The DC can be supplied to the outside of the inverter,
A power transmission method, wherein the DC voltage is measured, and the frequency at the time of the frequency conversion is made variable so that the measured DC voltage is constant.

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