JP2012100455A - Electric motor/power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor/power generation system capable of supplying a stable large current for the long term to a storage battery connected to an output side power generator, by enhancing feedback control from output to input.SOLUTION: An electric motor/power generation system, which is connected between an AC electric motor and an AC power generator with a pulley and a belt, includes: input control means that controls input power supplied to the AC electric motor; rectification means that rectifies output of the AC electric motor into a DC voltage; voltage conversion means that generates a low-voltage large current by stepping down an output voltage of the rectification means; storage means that stores power output from the voltage conversion means; and voltage monitor means that monitors a terminal voltage of the storage means. The voltage monitor means produces a predetermined control signal according to a monitor voltage, and the input control means controls input power supplied to the AC electric motor according to the control signal.

Description

  The present invention relates to an electric motor / power generation system in which rotating shafts of an electric motor and a generator are connected to each other using a pulley and a belt, and the electric generator is driven by the electric motor to generate electric energy.

  In recent domestic and international society, various small-scale auxiliary power generation systems have been widely used as a supplement to conventional large-scale power generation systems using nuclear power and thermal power from the viewpoint of environmental protection and prevention of global warming. It came to be advocated. As one of them, a so-called “electric power generation system” in which an electric motor and a generator are combined has been proposed, and many prior art documents have already been disclosed for such technology.

  For example, in Patent Literature 1, an electric motor and a generator are connected via a flywheel having a predetermined inertia, and electric power that can supply stable power by supplementing an unstable power generation source by sunlight or wind power.・ The power generation system is shown. Patent Document 2 discloses an electric / power generation system in which an electric motor and a generator are connected by a power transmission mechanism using a pulley and a belt to generate electric power, and output power from the generator is stored in a storage battery.

Utility Model Registration No. 3139275 Utility Model Registration No. 3154839

  However, in these conventional technologies, there is no stable feedback loop from the generator side that is the output to the input motor side, and the input side generated power is necessary and sufficient. There is a possibility that a situation in which unnecessary input power continues to be supplied to the side. Further, since the negative feedback action from the output side to the input side does not operate sufficiently, there is a possibility that the current flowing to the output side becomes excessive and the entire system becomes a runaway state.

  The present invention aims to solve such a conventional problem. More specifically, the feedback control from the output side to the input side is enhanced and connected to the generator on the output side. An object of the present invention is to provide an electric / power generation system capable of supplying a stable large current to a stored battery for a long time.

The electric / power generation system according to the first aspect of the present invention achieves the above-described object,
An input control means for controlling input power supplied to the AC motor in an electric motor / generator system comprising an AC motor, and the AC motor and an AC generator having rotating shafts connected to each other by a pulley and a belt, and the AC power generation Rectifying means for rectifying the output of the machine to DC voltage, voltage converting means for stepping down the DC voltage that is the output of the rectifying means to generate a large current of low voltage, and storage for storing the electric power output from the voltage converting means Means, and voltage monitoring means for monitoring the terminal voltage of the power storage means,
The voltage monitoring means generates a predetermined control signal according to the terminal voltage of the power storage means, and the input control means controls input power supplied to the AC motor according to the control signal. And

Moreover, the electric / power generation system according to the second aspect of the present invention is the above first aspect,
The diameter of the pulley provided on the rotating shaft of the AC generator is larger than the diameter of the pulley provided on the rotating shaft of the AC motor.

Moreover, the electric / power generation system according to the third aspect of the present invention is the above first or second aspect,
The current value supplied to the power storage means is extremely large compared to the current value supplied to the AC motor.

In addition, an electric motor / power generation system according to a fourth aspect of the present invention provides at least one of the first to third aspects,
The AC motor and the AC generator are a three-phase AC induction motor and a generator.

  The electric / power generation system according to the present invention realizes an electric / power generation system capable of stably supplying a large current over a long period of time to a storage battery connected to an output-side generator, despite a simple configuration. be able to.

  Embodiments that are the best mode for carrying out the present invention will be described below with reference to the accompanying drawings attached to the specification of the present application.

  First, a schematic configuration of an electric motor / power generation system 100 according to the present embodiment is shown in a block diagram of FIG. In the figure, a power receiving apparatus 101 is an apparatus for receiving electric power from a commercial three-phase AC power supply of AC 200 V and supplying it to the present system, and usually includes a power switch, a fuse, or a breaker. In some cases, various measuring devices such as an ammeter, a voltmeter, and a wattmeter may be included in the apparatus. Further, for example, a capacitor for the purpose of improving the power factor and suppressing the starting torque may be provided in the apparatus. In addition, since the power receiving apparatus 101 is not an essential component in the present embodiment, it can be omitted to configure the system.

  The AC power output from the power receiving apparatus 101 is supplied to the electric motor 103 via the input control apparatus 102. The input control device 102 is a device that adjusts and controls AC power supplied to the electric motor 103 in accordance with a control signal described later. It is possible to use various principles as the configuration of the apparatus. For example, as shown in FIG. 2a, the inductance of the reactor inserted in series and in parallel in each phase of the three-phase alternating current is used as a drive mechanism by a servo motor. It is also possible to use a device such as an inductive voltage regulator that controls the three-phase AC power by changing it mechanically.

  The motor 103 is a three-phase induction motor driven by normal three-phase AC power. In this embodiment, when a three-phase AC power supply of 200 VAC is applied as the motor 103, a 5-horsepower motor that flows about 5.5 A in phase current during no-load operation is used. However, it goes without saying that implementation of the present invention is not limited to such examples, and motors with different ratings or driving principles can be used.

  A pulley 104 is attached to the rotating shaft of the electric motor 103, and the pulley 104 is connected to a generator-side pulley 106 via a power transmission belt 105. Incidentally, as the power transmission belt 105, it is possible to use various modes of power transmission belts such as a normal flat belt and a V belt.

Incidentally, in the present embodiment, the diameter of the pulley 104 on the electric motor side is set to 18 cm, and the diameter of the pulley 106 on the generator side is set to 30 cm. Thus, for example, if the rotation speed of the electric motor 103 is set to 1,450 rpm, the rotation speed of the generator-side pulley 106 is

1,450 rpm × (18 cm / 30 cm) = 870 rpm
It becomes.

One feature of the present invention is that the diameter of the generator-side pulley is larger than the diameter of the motor-side pulley. In general, in the power transmission system using pulleys and belts as shown in FIG. 1, the torque of the driving motor is reduced by making the diameter of the pulley on the transmission side larger than the diameter of the pulley on the driving side. Is possible. Therefore, also in this embodiment, the diameter of the pulley 104 (18 cm) <the diameter of the pulley 106 (30 cm).
Thus, the driving torque of the electric motor 103 can be reduced.

  The generator 107 is a generator for three-phase alternating current, and in this embodiment, a generator having a capacity of 3 kW and 48 poles is used. In the present invention, it goes without saying that the conditions such as the diameter of the pulley and the number of poles of the generator are not limited to such examples. The generator 107 outputs AC 200V three-phase AC power, and the output AC power is supplied to the rectifier 108.

  The rectifier 108 is, for example, a three-phase bridge-type full-wave rectifier circuit as shown in FIG. 2b, and converts the three-phase AC power supplied from the generator 107 into DC. In this embodiment, when the operation is performed under the various conditions described above, a DC voltage of about DC 200 V can be obtained as the output of the rectifier 108.

  The DC power output from the rectifying device 108 is subsequently supplied to the voltage converter device 109 provided in the subsequent stage. The voltage converter device 109 is a normal DC-DC converter, and is a device that converts an input DC voltage value into an arbitrary DC voltage value. Here, an outline of the voltage converter device 109 is shown in the block diagram of FIG.

  As shown in the figure, in the voltage converter device 109, four power IGBTs (insulated gate / bipolar transistors) S1 to S4 connected in a full bridge system are arranged in a predetermined sequence (a set of S1, S4 and S2, S3). The DC 200V DC input to the apparatus is converted into a high-frequency rectangular wave voltage of several hundred kHz.

  The rectangular wave voltage obtained by such processing is stepped down to a low voltage by the high frequency transformer T1, further rectified by the diodes D1 and D2, and then the voltage converter via the smoothing circuit constituted by the reactor L1 and the capacitor C1. Output from the device 109. As a result, the DC voltage of 200 V DC supplied to the apparatus is converted into a DC voltage value that allows a large current to flow at a lower pressure.

  Incidentally, in this embodiment, the output voltage value of the voltage converter device 109 is set to DC 48V DC. However, the embodiment of the present invention is not limited to the voltage value, and is adjusted to the voltage of the battery to be used. For example, it is possible to set an arbitrary value such as DC12V or DC24V.

  The battery device 110 includes a battery group in which a plurality of batteries are connected in series or in parallel, and preferably includes a charge control circuit (not shown) for performing trickle charge or quick charge.

  In addition, there is no restriction | limiting in particular about the battery used in a present Example, Even if it is a general lead battery, or a nickel cadmium battery and a lithium ion battery, there is no problem. It is also possible to charge a super capacitor using an electric double layer as a battery by making a predetermined modification to the charge control circuit.

  As described above, in the electric motor / power generation system 1 according to the present embodiment, DC 200 V is stepped down to DC 48 V by the voltage converter device 109, and charging of the battery is started with power of DC 48 V × 30 A (about 1,440 W). Needless to say, in the case of a lead battery, lead dioxide used as an electrode thereof is electrolyzed by a charging voltage, and charging is performed by attaching charges (electrons) to the lead dioxide electrode. . In this embodiment, a storage battery block generally used in a small mobile transport vehicle such as an electric forklift is employed as the battery device 110. By the way, one storage battery block is composed of a combination of multiple small lead batteries in parallel and in series. Prepare this from the first block to the seventh block and connect the charging power to each block. Charging was performed while switching sequentially.

  The voltage monitoring device 111 is a device that monitors the terminal voltage of the battery device 110, generates a predetermined control signal according to the value of the terminal voltage, and sends this to the input control device 102 described above. A schematic configuration of the apparatus is shown in the block diagram of FIG. As shown in the figure, the voltage monitoring device 111 mainly includes a voltage detection unit 111a, a comparison calculation unit 111b, a reference voltage generation unit 111c, and a control signal transmission unit 111d.

  In order to suppress the influence on the terminal voltage of the battery device as much as possible, the voltage detection unit 111a is preferably composed of a voltage detection circuit having an extremely high input resistance such as a voltage follower. The detection voltage from the voltage detection unit 111a is supplied to the + side terminal of the comparison calculation unit 111b. At the same time, the reference voltage from the reference voltage generation unit 111c is also applied to the negative terminal of the comparison calculation unit 111b.

  The reference voltage generation unit 111c is a circuit that generates a predetermined reference voltage by using a constant voltage diode such as a Zener diode. In the case of this embodiment, a reference voltage of (DC48 + α) V is generated. To do. Incidentally, α is a so-called threshold voltage. For example, if this value is set to α = 0.5V, the terminal voltage of the battery device input to the + side terminal of the comparison calculation unit 111b exceeds DC48.5V. In addition, a predetermined control signal is generated by the comparison calculation unit 111b. Note that the value of the threshold voltage α can be arbitrarily set according to the operation of this system by a setting switch or the like (not shown) provided in the voltage monitoring device 111.

  The control signal sending unit 111d is a circuit that converts the control signal supplied from the comparison calculation unit 111b into a predetermined signal format such as RS232C or RS422 and sends the signal to the input control device 102. Note that, in a system including a lot of high-power related equipment such as an electric motor and a generator as in this embodiment, since the operation noise of the equipment is extremely large, the control signal is converted into a current loop signal resistant to noise and transmitted. It is preferable.

  In response to the signal, the input control device 102 that has received the control signal from the voltage monitoring device 111 changes the movable iron core of the reactor of the three-phase induction voltage regulator that constitutes the device to, for example, a predetermined servo mechanism (not shown). ), And the input value of the three-phase AC power applied to the electric motor 103 is controlled.

  For example, if the control signal from the voltage monitoring device 111 indicates information that the terminal voltage of the battery does not exceed a predetermined threshold, the input power to the motor 103 is reduced by reducing the inductance of the three-phase induction voltage regulator. Increase. On the other hand, if the control signal from the voltage monitoring device 111 indicates information indicating that the terminal voltage of the battery exceeds a predetermined threshold, the inductance of the three-phase induction voltage regulator is increased and the input power to the motor 103 is increased. Decrease.

  Note that, unless a special charging method such as rapid charging is performed, generally, the charging current to the battery automatically decreases as the battery is charged. As a result, the load on the generator 107 is reduced, and naturally the load on the motor 103 that drives the generator 107 is also reduced, so that the power consumption of the motor 103 is reduced and an energy saving effect is produced.

  In this embodiment, a trickle charging method is adopted as a charging mode. Needless to say, in the trickle charging method, the battery is not charged after the battery is used up, but is charged with the battery capacity remaining at about 20%. As a result, the magnitude of the inflow current at the start of charging of the battery can be suppressed, and an energy saving effect at the time of charging can be expected.

  Further, by adopting the trickle charging method, damage to the lead dioxide electrode due to a large current at the start of charging can be prevented. As a result, the life of the battery itself is extended, and the amount of lead dioxide discarded as industrial waste can be reduced, and good results are expected from the viewpoint of environmental conservation.

  As described above, according to the present embodiment, it is possible to obtain a large amount of DC output power at a low voltage on the output side of the motor / power generation system, so that a large number of batteries can be efficiently charged. Become. Moreover, since the terminal voltage of the battery is constantly monitored and the input power of the motor is optimally adjusted by a control signal corresponding to the battery terminal voltage, wasteful consumption of the input power can be suppressed.

  The embodiments of the present invention are not limited to the examples described above. For example, the shape and arrangement of each part constituting each of the examples, or the material thereof is the gist of the present invention. It goes without saying that changes can be made as appropriate according to actual embodiments without departing.

The configuration and method of the present invention described above can be used in an electric / power generation system in which a generator is driven by an electric motor to generate electric energy and a large number of batteries are charged with the generated electric power.

It is a block diagram which shows the structure of the electric motor / power generation system by the Example of this invention. It is a figure which shows the outline | summary of the input control apparatus and rectifier in the system of FIG. It is a figure which shows the outline | summary of the voltage converter apparatus in the system of FIG. It is a figure which shows the outline | summary of the voltage monitoring apparatus in the system of FIG.

DESCRIPTION OF SYMBOLS 100 ... Electric power generation system 101 ... Power receiving apparatus 102 ... Input control apparatus 103 ... Electric motor 104 ... Electric motor side pulley 105 ... Power transmission belt 106 ... Generator side pulley 107 ... Electric generator 108 ... Rectifier 109 ... Voltage converter apparatus 110 ... Battery Device 111 ... Voltage monitoring device 111a ... Voltage detection unit 111b ... Comparison operation unit 111c ... Reference voltage generation unit 111d ... Control signal sending unit

Claims (4)

An input control means for controlling input power supplied to the AC motor in an electric motor / generator system comprising an AC motor, and the AC motor and an AC generator having rotating shafts connected to each other by a pulley and a belt, and the AC power generation Rectifying means for rectifying the output of the machine to DC voltage, voltage converting means for stepping down the DC voltage that is the output of the rectifying means to generate a large current of low voltage, and storage for storing the electric power output from the voltage converting means Means, and voltage monitoring means for monitoring the terminal voltage of the power storage means,
The voltage monitoring means generates a predetermined control signal according to the terminal voltage of the power storage means, and the input control means controls input power supplied to the AC motor according to the control signal. Electric and power generation system.   The motor / power generation system according to claim 1, wherein a diameter of a pulley provided on a rotating shaft of the AC generator is larger than a diameter of a pulley provided on a rotating shaft of the AC motor.   3. The electric / power generation system according to claim 1, wherein a current value supplied to the power storage unit is extremely larger than a current value supplied to the AC motor. 4. The motor / power generation system according to claim 1, wherein the AC motor and the AC generator are a three-phase AC induction motor and a generator. 5.

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