JP2009195013A - Power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply system for saving energy consumption by combining a DC power supply and an AC power supply. <P>SOLUTION: This power supply system includes an AC line 5 which supplies AC power from an AC power supply 1, and a DC line 10 which supplies two or more systems of DC power from the DC power supply 3. The two or more systems of DC power have different voltages. An apparatus is enabled to select the DC power supply of the DC line 10 or the AC power supply of the AC line 5, so that an AC-DC converter 61 or the like arranged at the apparatus side is not required, and a loss caused by the conversion at the AC-DC converter can be eliminated or reduced, thus saving the energy consumption. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply system. In particular, the present invention relates to a power supply system that efficiently supplies power to commercially available electrical equipment used in a general household or office, and that can practice energy saving with low loss.

  Electric devices that are currently on the market generally use an AC power source that is drawn from an electric power company into a house or office, etc., from an outlet. Due to the demand for multifunction and high efficiency (energy saving) in recent electrical equipment, computerization that enables high-efficiency control, inverterization that enables efficient operation of power equipment such as motors with fine-tuned control, It is being advanced.

  A computer basically requires a low-voltage DC power supply of about 5V to 20V, and an inverter is a circuit for controlling power supply from DC DC (about 100V to 600V). These electric devices always have an AC / DC conversion circuit for converting an AC power source into DC. The AC / DC conversion circuit is realized by a diode bridge and a smoothing capacitor or the like. However, the AC / DC conversion circuit has a loss that occurs when a current flows through the diode, and wastes power as heat. There is a loss.

On the other hand, recently, battery technologies such as solar cells and fuel cells have been advanced, and in addition to the power supplied from the power company, it has changed to have a power source that does not use the AC power of the power company in the house or building. Have been doing. The power generated by the battery is DC DC, but the conventional power supply line in the home is AC, and most electrical devices are made to use AC power from a power company. The power supply is a system for supplying AC power to the AC power line in the house through a DC / AC converter. Here, for example, a DC / AC converter using an inverter circuit is used for the battery, and the battery has a loss of about 5 to 10%, and the current situation is that power is wasted as heat.
JP 2001-327100 A

  In the conventional power supply system, assuming that the electric device is used with the power generated by the battery, the AC power with a loss of about 5 to 10% in the DC / AC modification of the battery from the DC power of the battery. Is converted to Furthermore, in an AC / DC converter of an electric device, it is returned to DC power with a loss of about 5 to 10% and used. That is, in the DC / AC conversion and AC / DC conversion, a loss of about 5 to 20% is involved, and the power is discarded as heat. It is a problem to be considered as a power supply system that energy saving is required and that 10 to 20% of the energy generated by the battery introduced for that purpose is lost.

  An outline of a conventional power supply system will be described with reference to FIG. An AC power source 1 supplied from an electric power company is supplied to an AC switchboard 2 in a house or office. On the other hand, the entire output of the battery 3 such as a solar battery, a fuel cell, and a storage battery installed in the house is input to the DC / AC converter 4 to perform mutual coupling between the DC of the battery 3 and the AC power source 1. It is converted to AC power and input to the AC switchboard 2. The AC switchboard 2 has low power consumption in the house, and may return power to the AC power supply 1 when surplus power is generated from the battery 3.

  From the AC switchboard 2, the AC outlet 5c, the lighting 6 in the house, motor-related home appliances 7 such as air conditioners, computer-related equipment 8 called digital home appliances, mobile phones, etc. are charged via the AC line 5 in the home. AC power is conventionally supplied to the devices 9 and the like.

  For example, the illumination 6 draws in AC power, is converted into DC once by an AC / DC converter 61 constituted by, for example, a diode bridge and a capacitor, and a tube 63 by an inverter 62 constituted by a switching device such as a MOSFET. A high-frequency AC is supplied to the electrodes to cause glow discharge and light.

  For example, a motor 7 for driving a compressor of an air conditioner, for example, draws an AC power source and is converted into DC once by an AC / DC converter 71 composed of, for example, a diode bridge and a capacitor, and is composed of a switching device such as a MOSFET. It is converted into AC for driving the motor by the inverter 72 to drive the motor 73.

  For example, the computer 8 draws in AC power, is converted into a DC voltage of about 16 V for components constituting the computer by the AC / DC converter 81, and information processing is calculated.

  For example, the mobile phone charger 9 draws in AC power and is converted into a DC voltage of about 6 V for mobile phones by the AC / DC converter 91.

  In the above-described conventional power supply system, the DC / AC converter 4 for supplying the DC power of the battery into the house has a power loss of about 5 to 10%. Further, the AC / DC converters 61, 71, 81, 91, etc., which convert the drawn AC power source into DC included in each device, have a loss of about 5 to 10%. When the DC power of the battery is used, the DC is converted to AC and distributed in the house, and the electric equipment that uses the power is converted back to DC and used again. The present invention aims to promote energy saving by distributing and using the DC power of the battery as it is in DC, reducing the power loss of the double conversion.

  The present invention solves the above-mentioned problems, and the object of the present invention is to realize energy saving by reducing loss when converting from a DC power source such as a fuel cell to AC and then converting from AC to DC. It is to provide a power supply system.

  In order to solve the above problems, a power supply system according to the present invention includes a line for supplying AC power from an AC power supply for AC, a line for supplying DC power for at least two lines from a DC power supply, and And a device that draws power by selecting an AC power source or the DC power source, and the two or more series of DC DC powers have different voltages.

  Most information processing (power supply to computer chips, etc.) and power electronics-related devices assume DC power, and the power supply line depends on alternating current, so power is supplied by AC / DC conversion. Is called. For example, when using power generated by a solar cell (DC), power is returned to the general power supply side by DC / AC conversion, and AC power drawn into the device is converted to DC by AC / DC conversion and used. , DC, AC, and DC are converted in this order. If a device is operated using a DC power source such as a solar cell without converting it to an AC power source, the power loss due to the DC / AC converter and the DC / AC converter in the above-described DC / AC / DC conversion is reduced. it can.

  As a preferred embodiment, in the power supply system of the present invention, a line supplying at least n (n = 2 or more) series DC power from the DC power supply is transmitted by n + 1 DC wires. One of the DC wires is a COM terminal, and the other N DC wires have different voltages from the COM terminal. With this power supply system, DC power can be efficiently supplied with the least number of lines.

  As a preferred embodiment, the power supply system of the present invention includes at least one of a group of 5V, 10V, 16V, and 100V as a voltage of an n-series DC electric wire.

  Furthermore, as a preferred embodiment, the power supply system of the present invention is a battery in which the DC DC power supply includes at least one of a solar cell and a fuel cell, or a battery in which a solar cell and a fuel cell are connected in parallel. Yes, in a solar cell or fuel cell having a plurality of unit cells connected in series, from the end electrode of the plurality of unit cells connected in series, used as a lead-out COM terminal line, It is characterized in that a voltage smaller than the voltage of the entire battery is drawn from a part of a plurality of unit cells connected in series and used for a plurality of DC DC lines.

  In solar cells, fuel cells, and the like, the output voltage of the stack, which is the basic structure, is about several volts, and the required output voltage is secured by stacking this in series. In other words, even if the overall output voltage of the solar cell, fuel cell, and storage battery is 100V, the output of several to several tens of volts can be obtained directly from the battery without using a power conversion circuit, etc., depending on how the electrodes are removed. It can be taken out. The method of extracting power from only a part of the stacks stacked in series sometimes breaks the balance of the stack and causes a decrease in life, etc., but when the power exceeding the upper limit of the output DC power is required, By operating the AC / DC conversion circuit so as not to apply an excessive load on only a part of the stacks, a sufficient life can be secured.

  Furthermore, as a preferred embodiment, the power supply system of the present invention is a battery in which the DC DC power supply includes at least one of a solar cell and a fuel cell, or a battery in which a solar cell and a fuel cell are connected in parallel. In a solar cell or a fuel cell having a plurality of unit cells connected in series, a plurality of low-voltage DC DC voltages are obtained by a DC / DC converter that draws out the voltage of the whole battery and steps down the voltage. It is characterized by generating.

  In the embodiment of the present invention, unlike the above embodiment, the voltage of the entire battery stack is generated using a DC / DC power converter to generate a low voltage output. When a transformer step-down converter using an insulating transformer is used as the DC / DC converter, the output DC power can be arbitrarily set to ground and can be used very safely.

  Furthermore, as a preferred embodiment, in the power supply system of the present invention, in the power supply system, the DC power lines having a plurality of different voltages have different COM lines, and the lines for supplying the respective DC power are It is characterized in that power is transmitted by two.

  Furthermore, as a preferred embodiment, the power supply system of the present invention has a configuration in which a voltage smaller than the voltage of the entire battery is drawn from a part of a plurality of unit cells, and the low voltage is drawn. The battery stack is configured by a plurality of stacks connected in parallel, and the stack from which the low voltage is drawn is a stack having a larger current capacity than the whole.

  Furthermore, as a preferred embodiment, the power supply system of the present invention includes a plurality of stacks connected in parallel, and a switch is attached to the stack connected in parallel in the stack from which a low voltage is drawn. It is characterized by that.

  The power supply system of the present invention includes a line for supplying AC power from an AC power supply for AC and a line for supplying DC power for at least two lines or more from a DC power supply. Each power has a different voltage. With this configuration, it is possible to select a DC power source on the device side, it is not necessary to use an AC / DC converter provided on the device side, and loss due to conversion in the AC / DC converter can be eliminated or reduced. Energy saving can be realized.

(First embodiment)
The outline of the power supply system of this invention is demonstrated using FIG. As in the conventional example, an AC power source 1 supplied from an electric power company is supplied to an AC switchboard 2 in a house or office. On the other hand, a battery 3 such as a solar cell, a fuel cell, or a storage battery installed in a house is connected to a low voltage stack 3a, 3b, 3c,... As shown in FIG. It is piled up to become voltage. The entire output of the battery is input to the DC / AC converter 4, and the DC of the battery 3 and the AC power source 1 are mutually coupled to be converted into AC power, which is then input to the AC switchboard 2. The AC switchboard 2 has low power consumption in the house, and may return power to the AC power supply 1 when surplus power is generated from the battery 3.

  From the AC switchboard 2, the AC outlet 5c, the lighting 6 in the house, motor-related home appliances 7 such as air conditioners, computer-related equipment 8 called digital home appliances, mobile phones, etc. are charged via the AC line 5 in the home. AC power is conventionally supplied to the devices 9 and the like. In the power supply system of the present invention, a DC power supply line 10 is installed in parallel with the AC power supply line 5, and a DC outlet 10c for supplying DC power to each electric appliance is installed. Here, DC lines DC1, DC2, DC3,... Having different DC voltages taken out from different parts of the battery stack are taken out, and DC lines having two or more kinds of voltages are connected to the DC switchboard 11. The power is supplied and distributed in the house by the DC power line 10.

  For example, the illumination 6 draws in AC power, is converted into DC once by an AC / DC converter 61 constituted by, for example, a diode bridge and a capacitor, and a tube 63 by an inverter 62 constituted by a switching device such as a MOSFET. A high-frequency AC is supplied to the electrodes to cause glow discharge and light.

  For example, a motor 7 for driving a compressor of an air conditioner, for example, draws an AC power source and is converted into DC once by an AC / DC converter 71 composed of, for example, a diode bridge and a capacitor, and is composed of a switching device such as a MOSFET. It is converted into AC for driving the motor by the inverter 72 to drive the motor 73.

  For example, the computer 8 draws in AC power, is converted into a DC voltage of about 16 V for components constituting the computer by the AC / DC converter 81, and information processing is calculated.

  For example, the mobile phone charger 9 draws in AC power and is converted into a DC voltage of about 6 V for mobile phones by the AC / DC converter 91.

  Here, if each of the above devices is a device that operates together with a DC power source, the DC power source can be used from the power supply system of this embodiment as shown in FIG. By using a DC power source, the AC / DC converters 61, 71, 81, 91 included in each device need not be operated, loss due to the AC / DC converter can be reduced, and energy saving can be realized. Can do. For example, the DC line 10 is supplied with DC power having two kinds of voltages, and the respective voltages are set to 100V and 16V. 100V DC power is supplied to the air conditioner, and 16V DC power is supplied to the personal computer, so that the device can be operated without going through the AC / DC converter inside the air conditioner and the personal computer. In this case, the power consumption of the air conditioner and the personal computer can be reduced by the loss of the AC / DC converter.

  If the DC power supply line is not connected on each device side or if the DC power supply is insufficient, this system can be used if it is designed to operate using an AC / DC converter as in the conventional case. Energy saving can be realized flexibly according to the ability of the system. In other words, the device has inputs of a DC power source and an AC power source, and it is determined whether the device can be driven by the input from the DC power source. It is preferable to have a function of presenting the user with a switch to the power source.

(Second Embodiment)
The outline of the power supply system according to the second embodiment of the present invention will be described with reference to FIG.

  The difference from the first embodiment is a method of taking out a DC line having two or more kinds of voltages from the DC output of the battery. In the second embodiment, first, the voltage output of the entire battery is taken out and once converted into alternating current by the DC / AC converter 12. The insulation transformer 13 generates several necessary voltages. The DC outputs DC1, DC2, DC3,... Of several kinds of voltages are taken out by passing the DC / AC converter 14 again. A DC line having two or more kinds of voltages is supplied to the DC switchboard 11 and is distributed in the house by the DC power supply line 10.

  In the second embodiment, the DC / AC converter 12 and the AC / DC converter 14 are used to generate DC power supplies of several kinds of voltages. However, in the AC / DC converter 61 on the device side, the conversion matching between AC and DC is not sufficient for conversion to DC while being restricted by the frequency (60 Hz or 50 Hz) of the household AC power supply. Thus, the DC / AC converter 12 that receives the output of the battery has an advantage that the AC frequency can be determined so that the conversion matching is optimal with respect to the DC voltage output required in the DC line. Therefore, the way of using the DC / AC converter 12 and the AC / DC converter 14 as in the present embodiment is compared with the conventional DC / AC converter 4 for supplying power from the battery to the AC power supply line. Low loss and high efficiency.

  Furthermore, in the second embodiment, since the DC voltage is generated by the insulating transformer 13, the DC voltage is floating with respect to the battery potential. Therefore, even when a leakage occurs due to the grounding state of the device, current does not flow and the device can operate safely. Compared to the first embodiment, it can be operated as a power supply system with excellent safety.

(Third embodiment)
If power is taken out only from a part of the stack of fuel cells or the like stacked in series, the balance of the stack is lost and the life is shortened. Therefore, in the power supply system of the present embodiment, when the DC output is taken out from a part of the stack of the solar cell or the fuel cell, the stack portion of the battery corresponding to the DC output is configured by a plurality of stacks connected in parallel. Has been.

  By connecting a plurality of stacks in parallel, even if one stack is broken or performance is deteriorated, the other stacks are connected in parallel, so that the lifetime reduction can be suppressed. In addition, since the number of parallel battery stacks is increased in the portion corresponding to the DC output, the battery life is extended. That is, the stack on the low voltage side of the battery stack is configured by a plurality of stacks connected in parallel, and has a larger current capacity than the whole. Even if the low-voltage side DC output is taken out separately and only the low-voltage side supplies a larger amount of current, the current capacity on the low-voltage side is high and there is room, so that the life of the battery (stack) is suppressed.

  This embodiment is shown in FIG. The stacks 32 and 33 are connected in parallel to the low-pressure side stack (for example, 31a, 31b, and 31c) connected to the DC output of the battery 30 such as a fuel cell or a solar cell. Similar to the stack 31, like the stacks 33a, 33b, and 33c, the number of stacks corresponding to each voltage is connected in parallel. Although omitted in FIG. 3, for example, the stacks 32 a, b, and c are connected in parallel in the same manner as the stacks 31 and 33.

  The battery stack shown in FIG. 3, for example, 31a, etc., shows a portion corresponding to a predetermined voltage of the actual battery stack, and is a unit of each stack that is an actual physical configuration. It does not indicate. Also, the stacks 31a, b, c, etc. are not limited to three. Also, the number of parallel is not limited to three as in the stacks 31, 32, 33, and may be two or four or more.

  FIG. 4 shows a modification of the present embodiment. In FIG. 4, switches 34 are attached to the respective stacks 31, 32, and 33 that are connected in parallel (in FIG. 4, nine of 31, 32, and 33 are shown). The switch 34 can be realized by a relay or the like. By controlling the switching with the switch 34 so that the load is not concentrated on one stack, it is possible to prevent the life of the battery (stack) from being reduced. Switching by the switch 34 may be performed periodically by, for example, a timer, or may be switched by measuring usage time.

  As described above, the power supply system of the present invention achieves energy savings of 5 to 20% compared to conventional power supply systems having solar cells, fuel cells, storage batteries and other batteries in homes and buildings. it can.

1 is a schematic diagram of a power supply system according to a first embodiment of the present invention. Schematic diagram of a power supply system according to a second embodiment of the present invention Schematic diagram of a power supply system according to a third embodiment of the present invention Schematic of the modification of the power supply system which concerns on the 3rd Embodiment of this invention Schematic diagram of a conventional power supply system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 AC switchboard 3 Battery 3a, 3b, 3c Stack 4 DC / AC converter 5 AC line 5c AC outlet 6 Illumination 61, 71, 81, 91 AC / DC converter 7 Air conditioner 8 Computer 9 Cell phone charger 10 DC line 10c DC outlet 11 DC switchboard 12 DC / AC converter 13 Transformer 14 AC / DC converter 31, 32, 33 Battery stack 31a, 31b, 31c Stack 33a, 33b, 33c Stack

Claims (9)

A line for supplying AC power from an AC power source of AC;
A line that supplies DC power of at least two series of DC power from a DC power supply;
A device that draws power by selecting the AC power source or the DC power source, and
The power supply system according to claim 1, wherein the two or more series of direct current DC powers have different voltages. The power supply system according to claim 1,
A line for supplying at least n (n = 2 or more) series DC power from the DC power source is transmitted by n + 1 DC wires, and one of the DC wires is a COM terminal. The other N DC wires have different voltages from the COM terminal, respectively. The power supply system according to claim 2,
A power supply system comprising at least one of a group of 5V, 10V, 16V, and 100V as a voltage of an n-series DC electric wire. The power supply system according to claim 1,
The direct current DC power source includes at least one of a solar cell and a fuel cell, or is a battery in which a solar cell and a fuel cell are connected in parallel.
In a solar cell or a fuel cell having a plurality of unit cells connected in series, it is used as a lead-out COM terminal line from an end electrode of the plurality of unit cells connected in series, A power supply system, wherein a voltage smaller than the voltage of the whole battery is extracted from a part of a plurality of unit cells connected to each other and used for a plurality of DC DC lines. The power supply system according to claim 1,
The direct current DC power source includes at least one of a solar cell and a fuel cell, or is a battery in which a solar cell and a fuel cell are connected in parallel.
In a solar cell or a fuel cell having a plurality of unit cells connected in series, a plurality of low-voltage DC DC voltages are generated by a DC / DC converter that draws out the voltage of the entire battery and steps down the voltage. A power supply system characterized by that. In the power supply system according to claim 5,
A DC power line having a plurality of different voltages has a separate COM line, and two lines for supplying each DC power are transmitted by two power supply systems. The power supply system according to claim 4, wherein
The battery stack from which a voltage smaller than the voltage of the entire battery is drawn from a part of the plurality of unit cells, and the battery stack from which the low voltage is drawn is constituted by a plurality of stacks connected in parallel, The power supply system according to claim 1, wherein the stack from which the low voltage is drawn is a stack having a larger current capacity than the whole. The power supply system according to claim 7, wherein the power supply system includes a plurality of stacks connected in parallel, and a switch is attached to the stack connected in parallel in the stack from which a low voltage is drawn. , Power supply system. A line for supplying AC power from an AC power source of AC;
A line that supplies DC power of at least two series of DC power from a DC power source, and a device that draws power by selecting the AC power source or the DC power source,
The power supply system according to claim 1, wherein the two or more series of direct current DC powers have different voltages.

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