JP2009077604A - Ac input power leveling type power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce burden regulation of commercial power, to stably operate a load, and to suppress a peak current, with a minimum storage battery system. <P>SOLUTION: The AC input power leveling type power system is provided with: a converter 2 for converting AC power from a commercial power supply 1 into DC power; a storage battery 4 to be charged with the DC power; a composite circuit 5 having a first switching element for switching output of the converter 2 and a second switching element for switching output of the storage battery, for outputting after synthesizing DC power obtained by switching; an inverter 6 for converting output into AC power and supplying to load; and a control circuit 10 for receiving a measurement signal of DC current from the converter side and the storage battery side flowing to the composite circuit and a voltage measurement signal of the inverter, and exclusively switching the first switching element and the second switching element of the composite circuit according to the composite ratio set based on the current measurement signal and the voltage measurement signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an AC input level power supply system that supplies AC power to a load.

  In a power supply system that supplies alternating current power to a load and uses a storage battery and mainly cuts the peak, if the load power demand exceeds the contracted power with the power company, the load is separated from the commercial power supply. Electric power was supplied to the separated single load by converting direct current from the storage battery into alternating current using an inverter.

  However, in such a power supply system, the operation of the inverter for the purpose of cutting the load peak is an instantaneous drop or a short time operation of several minutes to about 30 minutes in order to avoid an increase in the size of the storage battery. The part could be cut, but it was not possible to achieve leveling of the entire power source using commercial power and storage batteries.

  Therefore, as an AC power supply system for solving such a problem, an AC input current from a commercial power supply is converted to DC by converter control, then DC output from a storage battery is added, and then converted to AC by inverter control. There is a method of supplying to a load (Patent Document 1).

In other words, this type of AC power supply system controls a converter that is supplied with a fixed amount of contract power from a commercial power supply so that it always outputs power equivalent to the average value of the amount of power supplied to the load. If the battery power exceeds the average value, the surplus power of the converter output is charged to the storage battery. Is supplied to the load.
Japanese Patent Application No. 2003-259596

  However, in this type of AC power supply system, the average value of the load is calculated to control the input power supply of the converter. This causes problems such as the inability to supply power to the load.

  For example, even if the load pattern is the same, if the peak of the previous day and that of the previous day is double, there is a problem that the power supply of the converter is small, power cannot be supplied to the load, and the load stops due to a voltage drop. is there.

Also, since the internal impedance of the storage battery changes depending on the charging status, the current charged in the storage battery is
Battery charge current = converter output current-load current
Battery charge current = converter output current x (load impedance / (battery impedance + load impedance)
It becomes.

  In this case, the current supplied to the load may be insufficient, and the operation of the load becomes unstable.

  The present invention has been made in order to solve the above-described problems, and combines and outputs commercial power and storage battery power at a set ratio, thereby minimizing storage battery equipment even when there is a load fluctuation depending on time zone. Thus, an object of the present invention is to provide an AC input level power supply system that can suppress fluctuations in the burden of commercial power, can operate the load stably, and can also suppress peak current.

  In order to achieve the above object, the present invention constitutes an AC input level power supply system by the following means.

  The invention corresponding to claim 1 is a converter that converts AC power supplied from a commercial power source into DC power, a storage battery that is charged by DC power output from the converter, and DC power output from the converter. A first switching element that switches and outputs, and a second switching element that switches and outputs DC power output from the storage battery, and is obtained by switching between the first switching element and the second switching element. A composite circuit that synthesizes and outputs the generated DC power, an inverter that converts the output of the composite circuit into AC power and supplies it to a load, a DC current that flows into the composite circuit from the converter, and the composite circuit from the storage battery Ammeters that measure the direct current flowing into each Means, voltage measuring means for measuring the input voltage of the inverter, each current measurement signal measured by the current measuring means and the voltage measurement signal measured by the voltage measuring means are inputted, and these current measurement signal and voltage Control means for exclusively controlling switching of the first switching element and the second switching element of the composite circuit according to a composite ratio set based on a measurement signal.

  According to a second aspect of the present invention, there is provided an AC input leveled power supply system according to the first aspect of the present invention, wherein the charging circuit includes a switching element that charges the storage battery by controlling charging of the DC power output from the converter. And the control means exclusively controls switching of the first switching element of the composite circuit and the switching element of the charging circuit.

  The invention corresponding to claim 3 is the AC input level power supply system according to claim 1 or claim 2, wherein the control means is configured such that the DC current flowing from the converter into the composite circuit exceeds a current set value. The burden of the storage battery is determined so that the direct current is equal to or less than the current set value, and the composite ratio is set.

  According to a fourth aspect of the present invention, in the AC input leveled power supply system according to the second aspect of the present invention, the control means is configured such that when the direct current flowing from the converter into the composite circuit is less than a set current value, The storage battery is charged by controlling the difference between the switching elements of the charging circuit.

  According to a fifth aspect of the present invention, there is provided an AC input leveled power supply system according to the third aspect of the present invention, wherein the control means is configured to temporarily increase an input voltage of the inverter measured by the voltage measuring means. When the value decreases, the current set value is gradually increased to reduce the load on the storage battery side, and the composite ratio is changed to gradually increase the load on the commercial power source side.

  According to the present invention, even if there is a load change depending on the time of day, it is possible to suppress the load fluctuation of the commercial power with the minimum storage battery equipment, and to operate the load stably and at the same time suppress the peak current. be able to.

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

  FIG. 1 is a circuit configuration diagram showing a first embodiment of an AC input leveled power supply system according to the present invention.

  In FIG. 1, 1 is a commercial power source, 2 is a converter that converts AC power input from the commercial power source 1 into DC power, and 3 is a switching element 3 that charges the storage battery 4 with DC power output from the converter 2. 1 is a charging circuit having 1.

  Reference numeral 5 denotes a composite circuit that receives DC power output from the converter 2 and DC power output from the storage battery 4 and combines these DC powers at a set ratio and outputs the composite circuit 5. The first switching element 5-1 corresponding to the output side of the storage battery 4 and the second switching element 5-2 corresponding to the output side of the storage battery 4 are provided.

  Furthermore, 6 is an inverter that converts the DC power output from the composite circuit 5 into AC power and supplies the AC power to the load 7.

  On the other hand, 8a is a first current measuring instrument that measures the direct current input from the converter 2 to the composite circuit 5, and 8b is a second current measuring instrument that measures the direct current input from the storage battery 4 to the composite circuit 5. Reference numeral 9 denotes a voltage measuring instrument that measures a DC voltage input to the inverter 6 from the composite circuit 5.

  Reference numeral 10 denotes a control circuit to which the composite input current signal measured by the first current measuring instrument 8a and the second current measuring instrument 8b and the inverter input voltage signal measured by the voltage measuring instrument 9 are input. The control circuit 10 gate-controls the first switching element 5-1 and the second switching element 5-2 of the composite circuit 5 at a composite ratio set based on the composite input current signal and the inverter input voltage signal. In addition, the switching element 3-1 of the charging circuit 3 is gate-controlled.

  Next, the operation of the AC input level power supply system configured as described above will be described with reference to the time chart shown in FIG.

  First, the control function of the control circuit 10 will be described. The switching element 5-1 corresponding to the output side of the converter 2 of the composite circuit 5 and the switching element 5-2 corresponding to the output side of the storage battery 4 are exclusively gate-controlled. To do. That is, when the switching element 5-2 corresponding to the output side of the storage battery 4 of the composite circuit 5 is turned on, the switching element 3-1 of the charging circuit 3 is not turned on. Further, both the switching elements 5-2 and the switching element 3-1 can be turned off simultaneously.

  Further, the switching element 5-1 corresponding to the output side of the converter 2 of the composite circuit 5 is turned ON / OFF with respect to the DC power converted from the AC power of the commercial power source 1 by the converter 2, and corresponds to the output side of the storage battery 4. The switching element 5-2 is turned on and off with respect to the DC power output from the storage battery 4. At this time, the switching element 5-1 and the switching element 5-2 are exclusively controlled. When the switching element 5-1 is ON, the switching element 5-2 is OFF, and when the switching element 5-2 is ON, the switching element 5-2 is OFF. 5-1 is set to OFF.

  Further, the control circuit 10 sets the ON / OFF ratio of the switching element 5-1 and the switching element 5-2 of the composite circuit 5 according to the composite ratio. Thereby, the sharing ratio between the DC power obtained by converting the AC power of the commercial power source 1 by the converter 2 and the DC power output from the storage battery 4 is determined.

  In this case, the gate control period of the switching element 5-1 and the switching element 5-2 is set to several kHz.

  The control circuit 10 having such a control function controls the switching element 5-1 and the switching element 5-2 of the composite circuit 5 to be ON / OFF based on the composite ratio, so that the inverter 6 converts the AC power of the commercial power source 1 into a converter. The DC power obtained by combining the DC power converted by 2 and the DC power output from the storage battery 4 can be constantly supplied.

  Now, when the direct current measured by the current measuring means 8a exceeds the current set value, the burden of the storage battery 4 is determined so that the direct current is less than the current set value, and the composite ratio is set. The first switching element 5-1 and the switching element 5-2 of the circuit 5 are exclusively switched as described above.

  Further, when the direct current measured by the current measuring means 8a is smaller than the current set value, the first switching element 5-1 of the composite circuit 5 is turned on and the second switching element 5-2 is turned off. Then, the switching element 3-1 of the charging circuit 3 is subjected to switching control to charge the storage battery 4 with a direct current corresponding to the difference between the direct current and the current set value.

  Further, when the first switching element 5-1 and the switching element 5-2 of the composite circuit 5 are switching-controlled by the composite ratio, if the load temporarily increases, the direct current of the storage battery 4 is reduced due to a decrease in the capacity of the storage battery 4. The voltage gradually decreases. Thereby, when the inverter input voltage measured by the voltage measuring instrument 9 has decreased, the current set value is gradually increased, so that the DC power on the commercial power source side, that is, the converter 2 side and the DC power on the storage battery 4 side are increased. By changing the sharing ratio, the load on the storage battery 4 side can be reduced, and the load on the commercial power source 1 side can be gradually increased.

  In this way, the load can be operated stably and at the same time the peak current can be suppressed.

  According to the first embodiment described above, the DC power obtained by converting the AC power supplied from the commercial power source by the converter 2 and the DC power output from the storage battery 4 are based on the DC current flowing into the composite circuit 5. Since the DC power obtained by the switching control of the first switching element 5-1 and the second switching element 5-2 of the composite circuit 5 is synthesized and output by the composite ratio set to When power is supplied to a load with load fluctuation, fluctuation of commercial power can be suppressed with the minimum storage battery equipment.

  Further, by changing the combined ratio of the DC power output from the converter 2 and the DC power output from the storage battery 4 to adjust the balance between the load fluctuation of the commercial power and the storage battery capacity, Can be suppressed, and the equipment cost can be reduced.

  Furthermore, although the output of the storage battery 4 and the output of the commercial power source 1, that is, the output of the converter 2 are apparently combined, they are insulated from each other, so that the output of the storage battery 4 is connected to the commercial power source 1. There is no wraparound.

The circuit block diagram which shows 1st Embodiment of the alternating current input level type | mold power supply system by this invention. The time chart for demonstrating the effect | action of the composite control of the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... AC power source, 2 ... Converter, 3 ... Charging circuit, 3-1 ... Switching element, 4 ... Rechargeable battery, 5 ... Composite circuit, 5-1 ... 1st switching element, 5-2 ... 2nd switching element , 6 ... Inverter, 7 ... Load, 8a, 8b ... Current measuring instrument, 9 ... Voltage measuring instrument, 10 ... Control circuit

Claims (5)

A converter that converts AC power supplied from commercial power into DC power;
A storage battery charged with DC power output from the converter;
A first switching element that switches and outputs DC power output from the converter; and a second switching element that switches and outputs DC power output from the storage battery, the first switching element and A composite circuit for combining and outputting DC power obtained by switching of the second switching element;
An inverter that converts the output of this composite circuit into AC power and supplies it to a load;
Current measuring means for measuring a direct current flowing into the composite circuit from the converter and a direct current flowing into the composite circuit from the storage battery, and
Voltage measuring means for measuring the input voltage of the inverter;
Each current measurement signal measured by the current measurement unit and the voltage measurement signal measured by the voltage measurement unit are input, and the composite circuit is set according to a composite ratio set based on the current measurement signal and the voltage measurement signal. An AC input level power supply comprising: control means for exclusively switching control of the first switching element and the second switching element, and suppressing power fluctuation of the commercial power supply against load fluctuation system. The AC input leveled power supply system according to claim 1,
A charging circuit having a switching element for charging the storage battery by charging control of DC power output from the converter is provided,
The control means exclusively controls switching of the first switching element of the composite circuit and the switching element of the charging circuit. In the AC input leveled power supply system according to claim 1 or 2,
The control means determines the burden on the storage battery and sets the composite ratio so that when the direct current flowing from the converter into the composite circuit exceeds the current set value, the direct current is less than the current set value. AC input leveling power supply system. The AC input level power supply system according to claim 2,
When the direct current flowing from the converter into the composite circuit is less than a set current value, the control means switches the switching element of the charging circuit to control the difference, and charges the storage battery. Leveled power supply system. The AC input level power supply system according to claim 3,
When the input voltage of the inverter measured by the voltage measuring means decreases due to a temporary load increase, the control means gradually increases the current set value to reduce the burden on the storage battery side, and the burden on the commercial power source side. The AC input level power supply system is characterized by changing the composite ratio to gradually increase.

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