JP2006288018A - Power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability by eliminating a slip ring and a brush. <P>SOLUTION: Power is taken out of a secondary winding without the slip ring and the brush by installing: a rectifier 31 that rectifies AC outputs from the secondary windings 27, 28 and 29; a switching element 33; and a rotary transformer 39 having a primary coil 36 and a secondary coil 38. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power generation device that is connected to an AC power source and converts electric power into mechanical power.

  Conventionally, this type of power generation apparatus uses a slip ring and a brush that short-circuit the secondary winding to pull out the connection from the secondary winding to the outside, connect a resistor, and extract a part of the power. The current of the primary winding at the start (starting) is suppressed or the speed is controlled (see, for example, Patent Document 1).

  FIG. 5 shows a circuit diagram of a conventional wire wound induction motor described in Patent Document 1. As shown in FIG. As shown in FIG. 5, the winding induction motor 2 connected to a three-phase AC power source (not shown) by the main contactor 1 short-circuits the secondary winding, so that a slip ring (not shown) and a brush Further, a short-circuit contactor 3 is connected, and a resistor 5 for suppressing a primary current at the start is connected.

  The brush pulling device 4 pulls up / down the brush from the slip ring by the control circuit 7. When a stop signal is input, the timer 6 measures the stop time, and the control circuit 7 When the measured time reaches the set time, the brush that prevents flashover is pulled down to prepare for the next start.

The resistor 5 can also be used as a variable speed electric motor when the resistance value is adjustable.
JP 2000-354387 A

  However, since the connection from the secondary winding on the rotor side is pulled out by the slip ring and the brush, and the connection to the short circuit and the resistor is made to this, in terms of reliability Had the problem of.

  In order to solve the above-described problem, a power generation apparatus according to the present invention includes a primary winding connected to an AC power source, a first object that generates a rotating magnetic field, and a secondary winding that receives the rotating magnetic field. A second object provided rotatably relative to the first object, a rectifier for rectifying the AC output from the secondary winding, and switching for converting the output of the rectifier to high-frequency power An element, a primary coil, a secondary coil, and a rotary transformer that transmits the high-frequency power. The rectifier, the switching element, and the primary coil are provided in the second object, and the secondary coil is provided. It is provided on the first object.

  Thereby, since transmission of the load electric power from the secondary winding can be performed with a configuration without a mechanical sliding portion by a slip ring or a brush, a highly reliable power generation device can be realized.

  Since the power generation device of the present invention has a structure without a mechanical sliding portion by a slip ring or a brush, high reliability can be realized.

  A first invention has a primary winding connected to an AC power source, and has a first object that generates a rotating magnetic field, a secondary winding that receives the rotating magnetic field, and the first object A second object provided relatively rotatably; a rectifier that rectifies the AC output from the secondary winding; a switching element that converts the output of the rectifier into high-frequency power; a primary coil and a secondary coil; A rotary transformer for transmitting the high-frequency power, wherein the rectifier, the switching element, and the primary coil are provided on the second object, and the secondary coil is provided on the first object. As a result, it is possible to take out the electric power from the secondary winding without the slip ring or the sliding part of the brush, and the reliability can be improved.

  In the second invention, the primary winding of the first invention has a three-phase configuration, so that a rotating magnetic field can be configured with a simple configuration, and there is no slip ring or brush sliding portion. Power can be taken out from the next winding, and reliability can be improved.

  According to a third aspect of the present invention, the primary winding of the first aspect of the present invention has a two-phase structure and is connected to a single-phase AC power source together with a phase advance capacitor, so that the single-phase is widely used in general homes and the like. Because it can be applied with a power supply, the usable range is extremely wide, and it is possible to extract power from the secondary winding without the slip ring or brush sliding part, thereby improving reliability. Will be able to.

  According to a fourth aspect of the present invention, the switching element according to any one of the first to third aspects is configured to be attached to a radiator having a fan effect, so that the cooling effect is maximized even in a high-frequency switching operation of the switching element. Since it can be utilized, a rotary transformer or the like can be configured with a small size, and the size and cost can be reduced.

  According to a fifth aspect of the present invention, the rectifier according to any one of the first to fourth aspects is mounted on a radiator having a fan effect, so that the rectifier can be used even when the current of the secondary winding is large. Since the maximum cooling effect can be utilized, the size and cost can be reduced.

  A sixth invention includes, in addition to the configuration of any one of the first to fifth inventions, a speed detection unit that detects a relative speed between the first object and the second object, and a speed setting unit, By controlling the output power from the secondary coil so that the error between the detection output of the speed detection means and the set value of the speed setting means is reduced, the loss of the secondary winding in variable speed operation is suppressed. Thus, a power generator capable of adjusting the speed and generating little heat can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a circuit diagram of a power generation device according to Embodiment 1 of the present invention. In FIG. 1, an electric motor 21 is connected from a three-phase AC power source 20 of 200 V, 50 Hz or 60 Hz, which is generally called low-voltage power. The electric motor 21 has three-phase primary windings 22, 23, and 24 connected to respective terminals of the three-phase AC power supply 20, and serves as a stator (stator) that generates a rotating magnetic field. 25. The second object 26 that is a rotor (rotor) is provided so as to be relatively rotatable with respect to the first object 25, and is a three-phase secondary that receives a rotating magnetic field from the first object 25. Windings 27, 28 and 29 are provided.

  Note that the configuration of the secondary winding is not limited to the three-phase that is the present embodiment, and a free configuration is possible. The number of turns and the cross-sectional area of the enameled wire to be used, etc. There is room for free design so that an appropriate voltage can be obtained in relation to the circuit.

  In the present embodiment, the second object 26 is further provided with an electronic circuit 30. The electronic circuit 30 rectifies the AC output from the secondary windings 27, 28, and 29. The rectifier 31 has six diodes in a three-phase full-wave connection, and the DC output from the rectifier 31 has a waveform with a small ripple voltage. A switching element 33 composed of an IGBT (Insulated Gate Bipolar Transistor), a diode 34, and a switching element 33 for receiving a DC voltage of the capacitor 32 and the capacitor 32 for smoothing and converting this to a high frequency power of 100 kHz. A drive circuit 35 connected to the gate terminal is provided for on / off driving at 100 kHz with an on-time ratio (duty ratio) of 45%.

  In the present embodiment, the drive circuit 35 operates using the DC voltage of the capacitor 32 as a power source. The second object 26 further includes a primary coil 36 and a reset coil 37. The primary coil 36 is between the capacitor 32 and the switching element 33, and the reset coil 37 is between the capacitor 32 and the diode 34. It is connected to the.

  The first object 25 has a secondary coil 38 magnetically coupled to the primary coil 36 and the reset coil 37, and constitutes a rotary transformer 39 that transmits high-frequency power from the electronic circuit 30. The secondary coil 38 is connected to diodes 40 and 41 with high speed recovery, a choke coil 42 and a capacitor 43, rectified and smoothed to direct current, and connected to a resistor 44 serving as a load. .

  FIG. 2 is a cross-sectional view of the first object 25 and the second object 26 of the power generation device according to Embodiment 1 of the present invention. In FIG. 2, the iron casing 50 is provided with vent holes 51 and 52 on the upper surface side and the lower side surface of FIG. 2 for cooling the internal heat generating portion. The primary winding 22 is wound around an iron core 53 realized by stacking silicon steel plates having a structure called a stator core and the like. Similarly, three terminals that are wound around the iron core 53 and are star-connected are drawn out from the vent hole 52.

  The second object 26 serving as the rotor is rotatable by attaching ball bearings 54 and 55 attached to the casing 50, and is attached to the iron core 57 and the iron core 57 on the rotor side that are shrinked on the shaft 56. Although the wound secondary winding 27 is shown in the figure, since the secondary winding has three phases in the present embodiment, the secondary windings 28 and 29 of other phases are similarly iron cores 57. It has been provided by wrapping around.

  The three terminals of the secondary windings 27, 28, and 29 that are star-connected are connected to the electronic circuit 30, and in particular, the rectifier 31 and the switching element 33 are attached to an aluminum radiator 58. In particular, in the present embodiment, the radiator 58 has a fan shape at the outer peripheral portion so as to increase the effect of sending wind in the axial direction by rotation, and has a fan effect.

  The primary coil 36 and the reset coil 37 connected from the electronic circuit 30 are wound around a ferrite core 59 having a cross-sectional shape (opened outward) in a katakana U shape, and rotate together with the shaft 56. It has become a thing. The stationary secondary coil 38 is also housed in a ferrite core 60 having a U-shaped cross section (however, opened inward), so that the second coil 38 is centered on the shaft 56. Even if the object 26 rotates, the primary coil 36 and the secondary coil 38 can be operated with the magnetic coupling firmly maintained so as to operate as a transformer.

  3A and 3B show operation waveforms of the switching element 33 and the like of the electronic circuit 30. FIG. 3A shows the gate voltage Vg of the switching element 33, FIG. 3B shows the collector current Ic of the switching element 33, and FIG. Shows the waveform of the voltage V2 supplied from the capacitor 43 to the resistor 44, respectively.

  In the present embodiment, the polarity of the rotary transformer 39 is a so-called forward converter, and the voltage generated in the secondary coil 38 from the diode 40 to the capacitor through the choke coil 42 while the switching element 33 is on. 43 and the resistor 44. During the OFF period of the switching element 33, the diode 40 is in the reverse blocking state, and the operation of circulating to the choke coil 42, the capacitor 43, and the resistor 44 is performed along the path passing through the diode 41. It has become a thing.

  For the on period Ton, a voltage equal to the DC voltage V1 of the capacitor 32 is applied to the primary coil 36 through the switching element 33, and a load current flows through the diode 40 according to the inductance of the primary coil 36. The current increases linearly.

  During the off period Toff, the collector current Ic of the switching element 33 becomes zero, and the current of the secondary coil 38 also disappears. However, due to the energy stored in the choke coil 42 during the on period, a current is passed through the capacitor 43 and the resistor 44. The portion of the magnetic energy stored in the primary coil 36 that cannot be extracted from the secondary coil 38 is regenerated to the capacitor 32 through the reset coil 37 and the diode 34, and the ferrite core 59, Even if the magnetic coupling that secures the gap between 60 to some extent is low, the collector voltage of the switching element 33 is prevented from becoming excessive.

  With the configuration as described above, the power generation device of the present embodiment is connected to the AC power supply 20 with a constant frequency, and the speed of the second object 26 that is a rotor is the synchronization speed under the condition that the synchronization speed is constant. When driving in a lower state, an alternating voltage having a frequency proportional to the speed of the difference, that is, a frequency proportional to the sliding speed is generated in the secondary windings 27, 28, and 29, and this is rectified to direct current by the rectifier 31. By the high frequency switching operation of the switching element 33, it is possible to return to the first object 25, which is a stator, again through the rotary transformer 39 while having a very advantageous configuration in terms of reliability without slip rings or brushes. .

  At this time, a considerable portion of the sliding power [W] calculated by the product of the sliding angular velocity (rad / s) and the load torque (Nm) can be drawn through the secondary coil 38 and consumed by the external resistor 44. Therefore, less power is processed in the second object 26, and heat generation in the second object 26 can be reduced.

  In particular, in the present embodiment, since the switching element 33 is turned on and off at 100 kHz and the rotary transformer 39 is operated at a high frequency, the rotary transformer 39, the capacitor 32, and the like can also be configured in a small size. -The cost can be reduced.

  In the resistor 44, power is consumed and heat is generated. However, if the resistor 44 is appropriately cooled or applied to a device having another load or heater that can be operated with a DC power source, Power can be supplied to them, and energy can be used rationally.

  In the present embodiment, the switching element 33 is attached to a radiator 58 having a fan effect, which has good heat conduction, and rotates on itself at a high speed for excellent heat transfer with air. In addition to obtaining a heat dissipation effect, the outer peripheral part has a twisted structure as a propeller (fan), generating an air current as shown by the dashed arrows in FIG. 58, a sufficient cooling effect can be obtained even when the switching element 33 is operated at a high frequency of 100 kHz, and the heat generating components of the first object 25 and the second object 26 are also downstream of the cooling air. Since it is cooled, the maximum cooling effect can be utilized.

  In the present embodiment, the rectifier 31 is also attached to the radiator 58 in the same manner. Therefore, even if the current of the secondary winding is large, the cooling effect of the rectifier 58 is a switching element. Similar to 33, an excellent product is obtained.

(Embodiment 2)
FIG. 4 shows a circuit diagram of the power generation device according to Embodiment 2 of the present invention. In FIG. 4, power is supplied from a single-phase 100 V 50/60 Hz AC power source 70, and the primary windings 71 and 72 are two phases provided at a position of an electrical angle of 90 degrees. A phase advance capacitor 73 is connected in series to the line 72 and is connected to an AC power source 70 to form a first object 74.

  Also in the second embodiment, as for the second object 26, the secondary windings 27, 28, 29, and the electronic circuit 30 are the same as those in the first embodiment, but the first object 74 is used. The secondary coil 75 provided in is configured as a converter generally referred to as a flyback in which the polarity is opposite to that of the first embodiment. The diode 76 and the capacitor 77 rectify the output of the secondary coil 75 to obtain a DC voltage.

  On the other hand, the speed detector 80 magnetically detects the rotational speed of the second object 26, that is, the relative speed between the first object 74 and the second object 26.

  The speed setting means 81 is for setting the rotational speed of the second object 26. The detection output of the speed detection means 80 and the set value of the speed setting means 81 are input by the amplifier 82, and the switching element 83 configured by IGBT. The on-time ratio (duty ratio) is determined. For example, when the actual rotational speed of the second object 26 is lower than the set value of the speed setting means 81, control is performed such that the ratio of the ON time of the switching element 83 increases. .

  A resistor 84 and a choke coil 85 are connected in series to the collector terminal of the switching element 83, and a diode 86 is further connected, and the DC voltage of the capacitor 77 is resisted by on / off operation of the switching element 83. In the operation consumed by the capacitor 84, an operation is performed in which the resistance value equivalently connected to the capacitor 77 changes corresponding to the on-time ratio of the switching element 83, and the on-time ratio is If it is larger, the resistance value of the equivalent resistive load connected to the capacitor 77 is lowered, and the voltage is lowered.

  Here, in the present embodiment, as a change due to a decrease in the resistance value of an equivalent resistance load connected to the capacitor 77, the power taken out from the secondary coil 75 changes in a decreasing direction. Yes.

  Therefore, the power obtained by subtracting the power drawn through the secondary coil 75 from the power supplied to the second object 26 from the primary windings 71 and 72 increases, and the second object 26 is accelerated. That is, the output power from the secondary coil 75 is adjusted so as to reduce the error. Other configurations are the same as those in the first embodiment.

  In the present embodiment, the speed is controlled by changing the on-time ratio of the switching element 83 while keeping the on-time ratio of the switching element 33 in the electronic circuit 30 constant. For example, the light from the light emitting element is received by the light receiving element provided in the electronic circuit 30 of the second object 26, and the light is changed to change the on-time ratio of the switching element 33. With such a configuration, a configuration in which the output power from the secondary coil 75 is adjusted so as to reduce the error may be realized.

  As described above, in each embodiment, the electronic circuit 30 in the second object 26 is configured with a one-stone converter, but is particularly limited to such a one-stone configuration. Instead, for example, two stone push-pull or four stone bridge connection may be used, and the type of switching element used may be a bipolar transistor or MOSFET other than IGBT.

  In addition to the power output from the secondary coil other than that consumed by the resistor as DC power, for example, when the AC power supply is three-phase, a separately-excited inverter using six stone thyristors and choke coils However, it may be converted to an AC power source to improve energy efficiency.

  As described above, it can be used for applications including a variable speed drive in a wide range of devices that supply power from an induction motor.

1 is a circuit diagram of a power generation device according to Embodiment 1 of the present invention. Cross section of the power generator Operation waveform diagram of the power generator Circuit diagram of power generation device according to Embodiment 2 of the present invention Circuit diagram of a conventional wound induction motor

Explanation of symbols

20, 70 AC power source 22, 23, 24, 71, 72 Primary winding 25 First object 26 Second object 27, 28, 29 Secondary winding 31 Rectifier 33 Switching element 36 Primary coil 38, 75 2 Next coil 39 Rotary transformer 58 Radiator 73 Phase advance capacitor 80 Speed detection means 81 Speed setting means

Claims (6)

A primary winding connected to an AC power source, a first object that generates a rotating magnetic field, and a secondary winding that receives the rotating magnetic field, and is rotatable relative to the first object. A second object provided; a rectifier that rectifies the AC output from the secondary winding; a switching element that converts the output of the rectifier into high-frequency power; a primary coil and a secondary coil; The rectifier, the switching element, and the primary coil are provided in the second object, and the secondary coil is provided in the first object. The power generator according to claim 1, wherein the primary winding has three phases. The power generator according to claim 1, wherein the primary winding has two phases, and is connected to a single-phase AC power source together with a phase advance capacitor. The power generation device according to any one of claims 1 to 3, wherein the switching element is attached to a radiator having a fan effect. The power generator according to any one of claims 1 to 4, wherein the rectifier is attached to a radiator having a fan effect. A speed detecting means for detecting a relative speed between the first object and the second object; and a speed setting means, and 2 for reducing an error between a detection output of the speed detecting means and a set value of the speed setting means. The power generator according to any one of claims 1 to 5, wherein the output power from the secondary coil is adjusted.

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