JP2012100507A - Power supply system and power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system and power conversion device for power supply system, capable of suppressing an increase in the capacity of a power converter.SOLUTION: A power supply system 10 is connected in series between a voltage type inverter 1 and a power system 2, and includes an interconnection reactor circuit 3 with interconnection reactors 7 and 8. The reactance of the interconnection reactor circuit 3 is set to be smaller in the case of autonomous operation than in the case of system interconnection operation.

Description

  The present invention relates to a power supply system that performs grid connection operation for supplying power from a power converter and a power system to a load, and a self-sustained operation for supplying power from the power converter to a load, and power for use in the power supply system The invention relates to a conversion device.

  Patent Documents 1 to 3 disclose a technology that includes a reactor between an inverter or an AC power supply and a load, and switches between reactance of the reactor at the time of outputting a large current and reactance of the reactor at the time of outputting a small current. Yes.

  As a specific example of the above technique, FIG. 6 shows a schematic configuration of a solar power generation system disclosed in Patent Document 1.

  The photovoltaic power generation system 60 shown in FIG. 6 is configured to increase or decrease the inductance by the inductors 65 to 67 in the filter coil 64 by operating the switches 62 and 63 according to the increase or decrease of the output current of the switch unit (inverter) 61. is there. Since the photovoltaic power generation system 60 can reduce the inductance by increasing the output current and obtain a filter effect corresponding to the output current, it is possible to suppress the distortion of the current regardless of the increase or decrease of the current.

  Conventionally, there is known a power supply system that performs grid connection operation for supplying power from an inverter (power converter) and a power system to a load, and a self-supporting operation for supplying power from the inverter to the load.

  Hereinafter, the power supply system will be described.

  First, an outline of grid interconnection operation will be described with reference to FIG.

  FIG. 7 is a diagram illustrating an example of a general system 70 for performing grid interconnection operation, which is configured by connecting a voltage type inverter 71 and a power system 72 via a grid reactor 73.

  When the voltage type inverter 71 is connected to the power system 72 via the interconnection reactor 73, the relationship between the output voltage of the voltage type inverter 71 and the system voltage of the power system 72 is expressed by the following formula (1). The In the following, ▲ VI • is the output voltage (vector) of the voltage-type inverter 71, VS • is the system voltage (vector) of the power system 72, and X is the reactance of the interconnection reactor 73.

▲ VI ・ ▼ = k ・ ▲ VS ・ ▼ (cosφ + jsinφ) (1)
Here, k is a predetermined constant for controlling the amplitude Vi of the output voltage ▲ VI · ▼ of the voltage type inverter 71 with respect to the amplitude Vs of the system voltage ▲ VS · ▼ of the power system 72, and j is an imaginary unit. .

  At this time, as for the electric power exchanged between the voltage type inverter 71 and the electric power system 72, the active power P is represented by the following mathematical formula (2), and the reactive power Q is represented by the following mathematical formula (3).

P = k ・ ▲ VS ・ ▼ ^ 2 ・ φ / X (2)
Q = (k · cos φ−1) ▲ VS · ▼ ^ 2 / X (3)
Here, φ indicates a phase difference between the output voltage ▲ VI · ▼ of the voltage type inverter 71 and the system voltage ▲ VS · ▼ of the power system 72, but is usually a very small value. As a result, the change in cos φ in Equation (3) becomes very small with respect to the change in amplitude Vs. Therefore, the reactive power Q is generally controlled by changing the constant k (controlling the amplitude Vi), while the active power P is generally controlled by changing the phase difference φ.

  Further, when the reactance X of the interconnection reactor 73 is increased, the overcurrent of the voltage type inverter 71 is reduced with respect to the transient fluctuation of the system voltage VS vs of the power system 72. As a result, the control of the output current of the voltage type inverter 71 becomes easy.

  However, as is clear from the above formulas (1) and (3), when the reactance X of the interconnection reactor 73 is increased, the amplitude Vi of the output voltage ▲ VI · ▼ of the voltage type inverter 71 is controlled when the reactive power Q is controlled. Need to be greatly changed. If the variable width of the amplitude Vi is increased in order to greatly change the amplitude Vi, it is necessary to increase the maximum value of the amplitude Vi, and accordingly, the capacity of the voltage type inverter 71 increases.

  Considering the above merits and demerits, the reactance X of the interconnection reactor 73 is generally set to a value of about 5 to 15% of the rated impedance of the voltage type inverter 71.

  In the specification of the present application, throughout, impedance is expressed in percent impedance, and reactance is expressed in percent reactance.

  For example, consider a case where the reactance X of the interconnection reactor 73 is 10% of the rated impedance of the voltage type inverter 71. In this case, in the power system 72, when a transient fluctuation of −10 to + 10% of the system voltage ▲ VS · ▼ occurs with respect to the rated voltage, the voltage type inverter 71 gives −100 to + 100% to the rated current. Overcurrent flows (provided that the output current of the voltage type inverter 71 is not controlled).

  The outline of grid interconnection operation has been described above.

  Incidentally, in recent years, the performance of new secondary batteries represented by nickel metal hydride batteries and lithium ion batteries has been remarkably improved. This new type secondary battery has a characteristic that a large capacity can be discharged in a short time.

  And in the said grid connection operation, the electric power supply system 80 shown in FIG. 8 is considered as a system which suitably utilized the characteristic of the said new secondary battery.

  The power supply system 80 shown in FIG. 8 has a battery (new type secondary battery) 74 connected to the voltage type inverter 71 and a switch between the power system 72 and the interconnected reactor 73 with respect to the system 70 shown in FIG. 75 is a system in which 75 is connected in series, and a load 76 is connected in parallel between the interconnection reactor 73 and the switch 75.

  The power supply system 80 performs leveling of the load 76 due to the discharge of the battery 74 by grid interconnection operation when the power system 72 is normal, while the voltage type inverter 71 performs independent operation to the load 76 when the power system 72 is abnormal. It is an example of a multifunctional battery power storage system that continues the power supply. Here, the leveling of the load is an operation in which the battery is charged at night when the power consumption is low and the power rate is lower than the daytime, and the charged battery is discharged to the load during the daytime when the power consumption is large. .

  That is, the power supply system 80 performs peak cutting of power due to the discharge of the battery 74 when the power system 72 normally supplies power to the load 76. Specifically, in this case, the power supply system 80 supplies the current from the battery 74 so as to compensate for the amount of power to be supplied to the load 76 exceeding the contracted power amount with the power company with the switch 75 closed. To discharge. The value of the current discharged at this time is about several C, for example, about 1C to 2C. Note that “1C” means a current value at which discharge is completed in exactly one hour when discharging with a constant current from a battery cell having a capacity corresponding to the nominal capacity value. Further, “yC” means a current value that is y times the current value corresponding to 1C (y is an arbitrary value). As described above, the power supply system 80 performs a grid-connected operation for supplying power to the load 76 from the voltage type inverter 71 and the power system 72 when the power system 72 is normally supplying power to the load 76. .

  On the other hand, the power supply system 80 detects a voltage when an abnormality occurs in power supply to the load 76 by the power system 72 due to an instantaneous voltage drop (hereinafter referred to as “instantaneous drop”) or a power failure in the power system 72. The type inverter 71 supplies power to the load 76 independently. Specifically, in this case, in the power supply system 80, the switch 75 is opened (opened), and from the battery 74, the power supply system 80 is several times (for example, 5 of 1C) in the grid connection operation depending on the capacity of the load 76. By discharging a current of 5C) which is a double current value, the voltage type inverter 71 operates to supply power to the load 76 alone. Thus, the power supply system 80 performs a self-sustained operation for supplying power from the voltage type inverter 71 to the load 76.

JP-A-8-126347 (published May 17, 1996) Japanese Patent Laid-Open No. 10-116690 (published May 6, 1998) JP 11-289766 A (published October 19, 1999)

  Here, the reactance of the interconnection reactor 73 in the power supply system 80, particularly during the independent operation, will be considered.

  As described above, in consideration of easily controlling the output current of the voltage type inverter 71, the reactance of the grid reactor 73 is the rated impedance of the voltage type inverter 71 during the grid connection operation of the power supply system 80. It is necessary to ensure a value of 5 to 15%.

  On the other hand, during the self-sustaining operation of the power supply system 80, for example, when the battery 74 discharges a current of 5C, the value of the current output from the voltage type inverter 71 is also almost five times. This is because the voltage-type inverter 71 has substantially the same output voltage in the case of the grid connection operation and the case of the independent operation, and only the output current changes according to the discharge power.

  When the value of the current output from the voltage type inverter 71 changes five times, the voltage drop in the interconnection reactor 73 also becomes five times. In other words, when the value of the current output from the voltage-type inverter 71 changes n times, the percent reactance of the reactance of the interconnection reactor 73 corresponds to n times before the change of the current value (n is Positive real number).

  The circuit that functions during the self-sustaining operation of the power supply system 80 is as shown in FIG. If the reactance of the grid reactor 73 is 10% of the rated impedance of the voltage-type inverter 71 during grid-connected operation with 1C discharge, the voltage-type inverter 71 during self-sustained operation with 5C discharge From the above, it corresponds to a value of 50% of the rated impedance.

  Here, when it is assumed that the load 76 is a pure inductive load, the amplitude Vd of the voltage (vector) ▲ VD • applied to the end of the load 76 is the voltage type inverter 71 during the self-sustaining operation. The output voltage ▲ VI · of the output voltage is reduced to 2/3 of the amplitude Vi.

  That is, when the voltage value dropped at the load 76 is 100% during the independent operation, the voltage value dropped at the interconnection reactor 73 is 50%. Therefore, it is clear from the following formula (4) that the amplitude Vd is reduced to 2/3 of the amplitude Vi.

Vd = 100 · Vi / (100 + 50) = 2 · Vi / 3 (4)
For the same reason, if the reactance of the grid reactor 73 is 10% of the rated impedance of the voltage-type inverter 71 during the self-sustaining operation by 5C discharge, the reactance during the grid connection operation by 1C discharge Is a value equivalent to 2% of the rated impedance. At this time, the reactance during the grid connection operation is not preferable because it makes it difficult to control the output current of the voltage type inverter 71.

  And in order to respond to the fall of the amplitude Vd, maintaining the ease of control of the output current of the voltage type inverter 71, the problem that it is necessary to increase the capacity | capacitance of the voltage type inverter 71 arises.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric power supply system that can suppress an increase in capacity of the electric power converter, and electric power conversion for use in the electric power supply system. To provide an apparatus.

  In order to solve the above problems, a power supply system of the present invention includes a power converter that can be connected to a power system, and supplies power to the load from the power converter and the power system. It is a power supply system capable of switching between system operation and independent operation for supplying power from the power converter to a load, and is connected in series between the power converter and the power system, And a connected reactor circuit including one or more connected reactors, the reactance of the connected reactor circuit in the case of performing the above-mentioned autonomous operation, and the reactance of the above-described connected reactor circuit in the case of performing the above-described system connected operation. It is characterized by being made smaller than the reactance.

  According to the above configuration, the reactance of the interconnection reactor circuit is smaller in the case of performing the autonomous operation than in the case of performing the grid interconnection operation. Thereby, it becomes possible to suppress the voltage drop in the interconnection reactor circuit during the self-sustaining operation while maintaining the controllability of the output current of the power converter during the grid interconnection operation.

  Therefore, the power supply system of the present invention can suppress a decrease in the amplitude of the voltage applied to the load during the self-sustained operation, and thus can suppress an increase in the capacity of the power converter. .

  In the power supply system of the present invention, the interconnected reactor circuit is connected in series with the two interconnected reactors connected in series between the power converter and the power system. And a switching circuit that is connected in parallel to one of the two interconnected reactors and that conducts when the autonomous operation is performed.

  According to the above configuration, during the self-sustaining operation, the switching circuit short-circuits both ends of the interconnected reactors connected in parallel, thereby reducing the reactance of the interconnected reactor circuit by the reactance of the interconnected reactor. It is possible. Thereby, it becomes easy to reduce the reactance of the interconnection reactor circuit during the self-sustaining operation.

  In the power supply system of the present invention, the interconnected reactor circuit is connected in parallel with the two interconnected reactors connected in parallel between the power converter and the power system. A switching circuit that is connected in series to one of the two interconnected reactors and that conducts when performing the autonomous operation is provided.

  According to the above configuration, the switching circuit reduces the reactance of the linked reactor circuit, which is a parallel circuit of a plurality of linked reactors, by conducting the connected reactors connected in series during self-sustained operation. It is possible. Thereby, it becomes easy to reduce the reactance of the interconnection reactor circuit during the self-sustaining operation.

  In the power supply system of the present invention, the interconnected reactor circuit includes a coil as the interconnected reactor, and a core portion that is made of a magnetic material and is insertable with respect to the coil. The insertion degree of the core part with respect to the coil can be adjusted. In the power supply system of the present invention, the interconnection reactor circuit includes a coil as the interconnection reactor and a contact provided so as to be able to contact the coil, and the contact with respect to the coil. It is possible to adjust the contact position.

  According to each configuration described above, the interconnected reactor circuit can continuously vary the reactance by adjusting the insertion degree of the core portion with respect to the coil or the contact position of the contact with the coil. Thereby, it becomes easy to reduce the reactance of the interconnection reactor circuit during the self-sustaining operation.

  In the power supply system of the present invention, the interconnected reactor circuit includes a saturable reactor as the interconnected reactor, and an AC power source connected to the saturable reactor and having a variable current value. It is characterized by providing.

  According to the above configuration, the interconnected reactor circuit can vary the reactance. Thereby, it becomes easy to reduce the reactance of the interconnection reactor circuit during the self-sustaining operation.

  In order to solve the above-described problem, a power converter according to the present invention is connected to a power converter in series with the power converter, and includes an interconnected reactor circuit including one or more interconnected reactors. The reactance of the interconnected reactor circuit when performing independent operation for supplying power from the power converter to the load is transferred from the power system connected to the power converter and the interconnected reactor circuit to the load. It is characterized by being made smaller than the reactance of the interconnection reactor circuit in the case of performing grid interconnection operation for supplying electric power.

  According to the above configuration, the reactance of the interconnection reactor circuit is smaller when the above-described power supply system of the present invention performs a self-sustained operation than when the power supply system performs a grid-connected operation. As a result, in the power supply system, it is possible to suppress the voltage drop in the grid reactor circuit during the independent operation while maintaining the ease of controlling the output current of the power converter during the grid grid operation. It becomes possible.

  As described above, the power conversion device of the present invention can be used as a power conversion device for use in the power supply system of the present invention.

  As described above, the power supply system of the present invention includes a power converter that can be interconnected with a power system, the grid connection operation that supplies power to the load from the power converter and the power system, and A power supply system capable of switching between self-sustained operation for supplying power from a power converter to a load, connected in series between the power converter and the power system, and one or Provided with an interconnected reactor circuit having a plurality of interconnected reactors, the reactance of the interconnected reactor circuit when performing the autonomous operation is made smaller than the reactance of the interconnected reactor circuit when performing the interconnected operation .

  Moreover, the power converter device of this invention is equipped with the power converter and the interconnection reactor circuit which is connected in series with the said power converter, and is provided with one or several interconnection reactors, The said power conversion Reactance of the interconnected reactor circuit when performing self-sustained operation for supplying power to the load from the transformer, and grid interconnection for supplying power to the load from the power system connected to the power converter and the interconnected reactor circuit The reactance of the interconnected reactor circuit when the operation is performed is made smaller.

  Therefore, the present invention has an effect that it is possible to suppress an increase in the capacity of the power converter.

It is a circuit diagram which shows the structure of the electric power supply system which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the structure of the electric power supply system which concerns on Embodiment 2 of this invention. It is a circuit diagram which shows the structure of the electric power supply system which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the structure of the electric power supply system which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the structure of the electric power supply system which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows schematic structure of the solar energy power generation system which concerns on a prior art. It is a circuit diagram which shows the structure of the general system for performing grid connection operation | movement. It is a circuit diagram which shows the structure of the electric power supply system which concerns on a prior art. It is a figure which shows the structure of the circuit which functions at the time of the independent operation of the electric power supply system shown in FIG.

  The form for implementing this invention is demonstrated below with reference to FIGS.

  In addition, in the structure of this invention demonstrated below, about the member which has the same function, it has shown using the same code | symbol, and detailed description of the member which has the same part or the same function is abbreviate | omitted.

[Embodiment 1]
FIG. 1 is a circuit diagram showing a configuration of a power supply system 10 according to the present embodiment.

  A power supply system 10 illustrated in FIG. 1 is a system that supplies power to a connected load 6. The power supply system 10 includes a voltage type inverter (power converter) 1, a connected reactor circuit 3, a new secondary battery (battery) 4, and a switch 5 that can be connected to the power system 2. .

  The electric power system 2, the switch 5, the interconnection reactor circuit 3, the voltage type inverter 1, and the new secondary battery 4 are connected in series in this order. The load 6 is connected in parallel between the switch 5 and the interconnected reactor circuit 3.

  The voltage type inverter 1 is a well-known power converter that converts a DC voltage applied from the new type secondary battery 4 into an AC voltage. In the power supply system 10, various devices capable of power conversion, such as a known PWM (Pulse Width Modulation) inverter, can be applied as the voltage type inverter 1.

  The power system 2 is a general power system configured by, for example, a commercial power source.

  The interconnected reactor circuit 3 includes one or a plurality of reactors (so-called interconnected reactors) that are connected in series between the inverter and the commercial power supply, particularly when performing grid-connected operation using the inverter and the commercial power supply. It is a circuit provided. The interconnected reactor circuit 3 is provided to enable control of the output current of the inverter by adjusting the voltage difference and the phase difference between both ends with the inverter.

  The new secondary battery 4 is a battery represented by a nickel metal hydride battery and a lithium ion battery, and has a characteristic that a large capacity can be discharged in a short time.

  The switch 5 is provided on a path between the electric power system 2 and the load 6, and is closed when the electrical connection of the same path is formed and is turned on, and the electrical connection of the same path is cut off. It is a general change-over switch that is opened (non-conducting) when opened.

  The load 6 is a target to which the power supply system 10 supplies power, and examples include industrial manufacturing equipment and various load equipment such as power supplies for measurement and control.

  Here, the interconnected reactor circuit 3 is configured to include a series circuit of the interconnected reactor 7 and the interconnected reactor 8 and a switch (switching circuit) 9 connected in parallel to the interconnected reactor 7.

  The reactance of the series circuit of the interconnected reactors 7 and 8 makes it easy to control the output current of the voltage-type inverter 1 and when the reactive power sent from the voltage-type inverter 1 to the power system 2 is controlled. The value is such that an increase in the amplitude of the output voltage of 1 can be sufficiently suppressed. Further, the reactance of the interconnection reactor 8 is a value that can generally remove a harmonic component caused by switching of the switching element in the voltage type inverter 1 including the switching element (not shown). However, the values of the reactances of the interconnecting reactors 7 and 8 are not quantitative because they vary depending on the configuration of the power supply system 10.

  The switch 9 is opened (non-conducting) to release a short circuit at both ends of the interconnecting reactor 7, while being closed and shorted (conducting) to short-circuit both ends of the interconnecting reactor 7. Switch.

  When the switch 9 is opened and both ends of the interconnection reactor 7 are not short-circuited, the reactance of the interconnection reactor circuit 3 becomes substantially equal to the reactance of the series circuit of the interconnection reactors 7 and 8.

  On the other hand, when the switch 9 is short-circuited and both ends of the interconnection reactor 7 are short-circuited, a voltage drop due to the reactance of the interconnection reactor 7 hardly occurs, and the interconnection reactor 7 is bypassed in the interconnection reactor circuit 3. Will be. Therefore, in this case, the reactance of the interconnection reactor circuit 3 is substantially equal to the reactance of the interconnection reactor 8.

  Although not shown for convenience, the power supply system 10 includes a filter capacitor that is connected in parallel to the load 6 and that functions as an LC filter together with the interconnected reactor circuit 3. The configuration in which the interconnected reactor circuit 3 and the filter capacitor are combined can remove harmonic components caused by switching of the switching element of the voltage type inverter 1.

  When the power system 2 normally supplies power to the load 6, the power supply system 10 performs load leveling due to discharge of the new secondary battery 4 and peak cut of power supplied from the power system 2. . Specifically, in this case, the power supply system 10 is configured so that the power to be supplied to the load 6 in a state in which the switch 5 is closed compensates for the amount exceeding the contracted power amount with the power company. The current is discharged from 4 (peak cut). As described above, the power supply system 10 performs a grid-connected operation for supplying power to the load 6 from the voltage type inverter 1 and the power system 2 when the power system 2 normally supplies power to the load 6. .

  More specifically, in the grid connection operation of the power supply system 10, the amplitude and phase of the output voltage of the voltage type inverter 1 are matched (synchronized) with the amplitude and phase of the output voltage of the power system 2, and these are linked. Make it. When the amplitude and / or phase of the output voltage of the voltage type inverter 1 is changed from this connected state, a current flows from the voltage type inverter 1. Further, the power supply system 10 includes a current control device (not shown), and adjusts the amplitude so that the phase of the current flowing from the voltage type inverter 1 matches the phase of the voltage of the power system 2 (so-called so-called). , Power factor 1 operation).

  Furthermore, the switch 9 is opened while the grid connection operation of the power supply system 10 is performed, whereby both ends of the grid reactor 7 are not short-circuited. At this time, the reactance of the connected reactor circuit 3 is substantially equal to the reactance of the series circuit of the connected reactors 7 and 8. Therefore, in the power supply system 10, the output current of the voltage type inverter 1 can be easily controlled, and when the reactive power of the voltage type inverter 1 is controlled, the amplitude of the output voltage of the voltage type inverter 1 is sufficiently increased. Can be suppressed.

  On the other hand, the power supply system 10 allows the voltage type inverter 1 to supply power to the load 6 alone when an abnormality occurs in the power supply to the load 6 by the power system 2 due to an instantaneous drop or a power failure in the power system 2. Supply. Specifically, in this case, the power supply system 10 is configured such that the switch 5 is opened and the new secondary battery 4 is several times as large as that in the grid connection operation according to the capacity of the load 6 (for example, 5 times that of 1C). By discharging the current of 5C) which is the current value, the voltage type inverter 1 operates to supply power to the load 6 independently. As described above, the power supply system 10 performs a self-sustained operation for supplying power from the voltage-type inverter 1 to the load 6.

  Further, the switch 9 is short-circuited while the electric power supply system 10 is being operated independently, whereby both ends of the interconnection reactor 7 are short-circuited. At this time, the reactance of the interconnected reactor circuit 3 is substantially equal to the reactance of the interconnected reactor 8. That is, the reactance of the grid reactor circuit 3 when the power supply system 10 is operated independently is smaller than the reactance of the grid reactor circuit 3 when the grid connection operation of the power supply system 10 is performed. ing.

  Thereby, in the power supply system 10, it is possible to suppress a voltage drop in the interconnected reactor circuit 3 during the self-sustained operation, and thus it is possible to suppress a decrease in the amplitude of the voltage applied to the end portion of the load 6. Is possible.

  Note that the switch 9 is opened when the switch 5 is short-circuited and is short-circuited when the switch 5 is opened. Here, the configuration for short-circuiting or opening the switch 9 is to control the opening / closing of the switch 9 using logic signals corresponding to the short-circuiting and opening of the switch 9 at the high level and the low level, respectively. However, there is no particular limitation. Further, the short circuit and the open circuit of the switch 5 and the short circuit and the open circuit of the switch 9 may be performed independently of each other, or may be performed in conjunction with each other.

  As described above, the power supply system 10 can obtain optimum reactance in the grid reactor circuit 3 in both grid grid operation and self-sustained operation that discharges a large current for a short time. . Thereby, the power supply system 10 can suppress an increase in the capacity of the voltage type inverter 1.

  Here, the capacity required by the voltage type inverter 71 of the power supply system 80 shown in FIG. 8 is compared with the capacity required by the voltage type inverter 1 of the power supply system 10. In addition, both the power supply system 80 and the power supply system 10 shall perform 1 C discharge at the time of grid connection operation, and 5 C discharge at the time of independent operation, respectively.

  In the following comparison, at the time of grid connection operation, the reactance of the grid reactor 73 and the reactance of the grid reactor circuit 3 are 10% of the rated impedance of the voltage type inverter of the corresponding power supply system. To do.

  In the grid reactor circuit 3, the reactance of the grid reactor 7 is 9.8% of the rated impedance of the voltage-type inverter 1 during grid grid operation, and the reactance of the grid reactor 8 is the same. The value is 0.2% of the rated impedance.

  First, a specific configuration example of the power supply system 80 is shown below.

[Configuration Example of Power Supply System 80]
・ Capacity of load 76: 500 kVA (kilovolt ampere)
・ Capacity required for peak cut of load 76 during grid connection operation: 100 kVA maximum
・ Reactance value of interconnection reactor 73 During grid interconnection operation: 10% of rated impedance of voltage-type inverter 71
Independent operation: 50% of the rated impedance of voltage type inverter 71
・ Capacity of interconnected reactor 73 during self-sustaining operation: 500/50/100 = 250 kVA
From the above configuration example, it was found that the capacity required by the voltage type inverter 71 of the power supply system 80 was 500 kVA + 250 kVA = 750 kVA.

  Subsequently, a specific configuration example of the power supply system 10 will be described below.

[Configuration Example of Power Supply System 10]
-Capacity of load 6: 500 kVA
-Capacity required for peak cut of load 6 during grid-connected operation: 100 kVA maximum
・ Reactance value of interconnection reactor 7 During grid interconnection operation: 9.8% of rated impedance of voltage inverter 1
Self-sustained operation: No need to consider because interconnected reactor 7 is bypassed ・ Reactance value of interconnected reactor 8 During interconnected operation: 0.2% of rated impedance of voltage-type inverter 1
Independent operation: 1% of the rated impedance of voltage type inverter 1
・ Capacity of interconnection reactor circuit 3 at the time of self-sustaining operation: 500 · 1/100 = 5 kVA
From the above configuration example, it was found that the capacity required by the voltage type inverter 1 of the power supply system 10 was 500 kVA + 5 kVA = 505 kVA.

  As described above, it was found that the voltage type inverter 1 of the power supply system 10 can be realized with a smaller capacity than the voltage type inverter 71 of the power supply system 80.

[Embodiment 2]
FIG. 2 is a circuit diagram showing a configuration of power supply system 20 according to the present embodiment.

  The power supply system 20 shown in FIG. 2 is different from the power supply system 10 shown in FIG. 1 in that it includes a connected reactor circuit 13 instead of the connected reactor circuit 3, and in other respects, the power supply system 20 shown in FIG. The power supply system 10 shown in FIG.

  The interconnected reactor circuit 13 includes a parallel circuit of the interconnected reactor 17 and the interconnected reactor 18 and a switch (switching circuit) 19 connected in series to the interconnected reactor 17.

  The reactance of the interconnection reactor 18 has the same value as the reactance of the series circuit of the interconnection reactors 7 and 8 (see FIG. 1). Furthermore, the reactance of the parallel circuit of the interconnection reactors 17 and 18 is the same value as the reactance of the interconnection reactor 8 (see FIG. 1).

  The switch 19 is disconnected (non-conducting) to electrically disconnect the interconnecting reactor 17 from the interconnecting reactor circuit 13, while being closed and short-circuited (conducting) to connect the interconnecting reactor 17. This is a general changeover switch that is electrically connected to the system reactor circuit 13.

  When the switch 19 is opened and the interconnection reactor 17 is electrically disconnected from the interconnection reactor circuit 13, the reactance of the interconnection reactor circuit 13 is substantially equal to the reactance of the interconnection reactor 18.

  On the other hand, when the switch 19 is short-circuited and the interconnection reactor 17 is electrically connected to the interconnection reactor circuit 13, the reactance of the interconnection reactor circuit 13 is equal to the parallel circuit of the interconnection reactors 17 and 18. It becomes approximately equal to reactance.

  The power supply system 20 performs a grid interconnection operation and a self-sustaining operation based on the same operation principle as that of the power supply system 10.

  Further, while the grid connection operation of the power supply system 20 is performed, the switch 19 is opened, and thereby the grid reactor 17 is electrically disconnected from the grid reactor circuit 13. At this time, the reactance of the interconnection reactor circuit 13 is substantially equal to the reactance of the interconnection reactor 18. Therefore, in the power supply system 20, the output current of the voltage type inverter 1 can be easily controlled, and when the reactive power sent from the voltage type inverter 1 to the power system 2 is controlled, An increase in amplitude can be sufficiently suppressed.

  Further, the switch 19 is short-circuited during the self-sustaining operation of the power supply system 20, whereby the interconnecting reactor 17 is electrically connected to the interconnecting reactor circuit 13. At this time, the reactance of the interconnection reactor circuit 13 is substantially equal to the reactance of the parallel circuit of the interconnection reactors 17 and 18. That is, the reactance of the grid reactor circuit 13 when the power supply system 20 is operated independently is smaller than the reactance of the grid reactor circuit 13 when the grid connection operation of the power supply system 20 is performed. ing.

  Thereby, in the power supply system 20, since it becomes possible to suppress the voltage drop in the interconnection reactor circuit 13 during the independent operation, the decrease in the amplitude of the voltage applied to the end portion of the load 6 is suppressed. Is possible. In other words, in the power supply system 20, there is little increase in the capacity of the voltage type inverter 1 for suppressing the decrease.

  Note that the switch 19 can have the same configuration as the switch 9 (see FIG. 1). In addition, the short circuit and the open circuit of the switch 5 and the short circuit and the open circuit of the switch 19 may be performed independently of each other or may be performed in conjunction with each other.

  As described above, the power supply system 20 can obtain optimum reactance in the grid reactor circuit 13 in both grid grid operation and self-sustained operation that discharges a large current for a short time. . Thereby, the power supply system 20 can suppress an increase in the capacity of the voltage type inverter 1.

  Note that each of the interconnection reactor circuit 3 shown in FIG. 1 and the interconnection reactor circuit 13 shown in FIG. 2 is configured to include two interconnection reactors and one switch. It is not limited, The structure provided with three or more interconnection reactors may be sufficient, and the structure provided with two or more switches may be sufficient.

[Embodiment 3]
FIG. 3 is a circuit diagram showing a configuration of power supply system 30 according to the present embodiment.

  The electric power supply system 30 shown in FIG. 3 is different from the electric power supply system 10 shown in FIG. 1 in that the electric power supply system 30 includes the interconnection reactor circuit 23 instead of the interconnection reactor circuit 3. The power supply system 10 shown in FIG.

  The interconnected reactor circuit 23 includes a coil (connected reactor) 27 and a core (core portion) 28.

  The core 28 is made of a magnetic material such as ferrite, iron, amorphous magnetic material, or sendust alloy, and is provided so as to be insertable into the coil 27.

  The core 28 can change the degree of insertion into the coil 27 by, for example, a step motor or an ultrasonic motor (not shown) whose rotational position is controlled by a pulse signal of a control device (not shown). .

  The power supply system 30 is capable of controlling the reactance of the interconnected reactor circuit 23 according to the degree of insertion of the core 28 into the coil 27. Specifically, the greater the insertion amount of the core 28 into the coil 27, the greater the reactance of the interconnection reactor circuit 23, and the smaller the insertion amount, the smaller the reactance of the interconnection reactor circuit 23.

  The power supply system 30 performs a grid interconnection operation and a self-sustaining operation based on the same operation principle as that of the power supply system 10.

  During the grid interconnection operation of the power supply system 30, the reactance of the interconnection reactor circuit 23 is adjusted to the series circuit of the interconnection reactors 7 and 8 by adjusting the insertion amount of the core 28 with respect to the coil 27 (see FIG. 1). The same value as the reactance of.

  On the other hand, during the self-sustaining operation of the power supply system 30, the reactance of the interconnection reactor circuit 23 is reduced to the same value as the reactance of the interconnection reactor 8 (see FIG. 1) by reducing the amount of insertion of the core 28 into the coil 27. To do.

  As described above, the power supply system 30 can obtain an optimum reactance in the grid reactor circuit 23 in both the grid grid operation and the self-sustained operation that discharges a large current for a short time. . Thereby, the power supply system 30 can suppress an increase in the capacity of the voltage type inverter 1.

  Further, the power supply system 30 can finely control the reactance by continuously changing the reactance of the interconnected reactor circuit 23 according to the degree of insertion of the core 28 into the coil 27.

[Embodiment 4]
FIG. 4 is a circuit diagram showing a configuration of power supply system 40 according to the present embodiment.

  The power supply system 40 shown in FIG. 4 is different from the power supply system 10 shown in FIG. 1 in that it includes a connected reactor circuit 33 instead of the connected reactor circuit 3. The power supply system 10 shown in FIG.

  The interconnected reactor circuit 33 includes a coil (connected reactor) 37, a donut-shaped core 38, and a contact 39 provided so as to be able to contact the coil 37.

  The interconnected reactor circuit 33 is configured by using a so-called single-turn variable output voltage transformer typified by Slidac (registered trademark).

  In the slidac, a toroidal core (core 38) made of the same material as that of the core 28 is wound with a copper wire (coil 37), and a contact 39 with a knob (not shown) is provided thereon to extract an output voltage. . The slider can change the inductance (reactance) almost continuously by turning the knob to change the position of the contact 39. Further, the interconnected reactor circuit 33 has a relatively small overall volume because the core 38 is annular. The knob can be rotated by, for example, a step motor or an ultrasonic motor (not shown) whose rotational position is controlled by a pulse signal of a control device (not shown).

  The power supply system 40 is capable of controlling the reactance of the interconnected reactor circuit 33 according to the contact position of the contact 39 with the coil 37.

  The power supply system 40 performs a grid interconnection operation and a self-sustaining operation based on the same operation principle as that of the power supply system 10.

  When the power supply system 40 is connected to the grid, the contact position of the contact 39 with respect to the coil 37 is adjusted to change the reactance of the linked reactor circuit 33 to the series circuit of the linked reactors 7 and 8 (see FIG. 1). ) The reactance is the same value.

  On the other hand, during the self-sustained operation of the power supply system 40, the reactance of the interconnection reactor circuit 33 is set to the same value as the reactance of the interconnection reactor 8 (see FIG. 1) by moving the contact position of the contact 39 with the coil 37. And

  As described above, the power supply system 40 can obtain an optimum reactance in the grid reactor circuit 33 in both the grid grid operation and the self-sustained operation that discharges a large current for a short time. . Thereby, the power supply system 40 can suppress an increase in the capacity of the voltage type inverter 1.

  Further, the power supply system 40 can finely control the reactance by continuously changing the reactance of the interconnected reactor circuit 33 in accordance with the contact position of the contact 39 with the coil 37.

[Embodiment 5]
FIG. 5 is a circuit diagram showing a configuration of power supply system 50 according to the present embodiment.

  The electric power supply system 50 shown in FIG. 5 is different from the electric power supply system 10 shown in FIG. 1 in that it includes an interconnection reactor circuit 43 instead of the interconnection reactor circuit 3. The power supply system 10 shown in FIG.

  The interconnected reactor circuit 43 includes a saturable reactor (connected reactor) 47 and an AC power supply 48 connected to the saturable reactor 47.

  The saturable reactor 47 is a well-known reactor that can reduce the reactance by saturating an iron core (not shown) by an alternating current supplied from the alternating current power supply 48. When the alternating current supplied from the alternating current power supply 48 exceeds a predetermined value (amplitude), the iron core is saturated, and the reactance of the saturable reactor 47 can be reduced.

  The power supply system 50 is capable of controlling the reactance of the interconnected reactor circuit 43 according to the current value supplied to the saturable reactor 47 from the AC power supply 48.

  The power supply system 50 performs a grid interconnection operation and a self-sustaining operation based on the same operation principle as that of the power supply system 10.

  During the grid connection operation of the power supply system 50, the reactance of the grid reactor circuit 43 is set in series with the grid reactors 7 and 8 by adjusting the current value supplied from the AC power supply 48 to the saturable reactor 47. The value is the same as the reactance of the circuit (see FIG. 1).

  On the other hand, during the self-sustaining operation of the power supply system 50, the reactance of the interconnected reactor circuit 43 is increased by increasing the value of the current supplied from the AC power supply 48 to the saturable reactor 47 (saturating the iron core). The value is the same as the reactance of (see FIG. 1).

  As described above, the power supply system 50 can obtain the optimum reactance in the grid reactor circuit 43 in both the grid grid operation and the self-sustained operation that discharges a large current for a short time. . Thereby, the power supply system 50 can suppress an increase in the capacity of the voltage type inverter 1.

  Furthermore, a power conversion device including the voltage type inverter 1 and any one of the interconnected reactor circuits 3, 13, 23, 33, and 43 is also included in the scope of the present invention. This power converter can be suitably used as a power converter for use in the power supply system of the present invention.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention relates to a power supply system that performs grid connection operation for supplying power from a power converter and a power system to a load, and a self-sustained operation for supplying power from the power converter to a load, and power for use in the power supply system It can be used for a conversion device.

1 Voltage type inverter (power converter)
2 Power system 3 Reactor circuit 4 New secondary battery (battery)
5 Switch 6 Load 7 Linked reactor 8 Linked reactor 9 Switch (switching circuit)
10 Power Supply System 13 Linked Reactor Circuit 17 Linked Reactor 18 Linked Reactor 19 Switch (Switching Circuit)
20 Power supply system 23 Linked reactor circuit 27 Coil (linked reactor)
28 Core (core part)
30 Power supply system 33 Interconnection reactor circuit 37 Coil (interconnection reactor)
39 Contact 40 Power supply system 43 Interconnected reactor circuit 47 Saturable reactor 48 AC power supply 50 Power supply system

Claims (7)

Equipped with a power converter that can be connected to the power system,
A power supply system capable of switching between grid connection operation for supplying power to the load from the power converter and the power system, and independent operation for supplying power to the load from the power converter,
It is connected in series between the power converter and the power system, and includes a connected reactor circuit including one or more connected reactors,
A power supply system, wherein a reactance of the interconnected reactor circuit when performing the independent operation is made smaller than a reactance of the interconnected reactor circuit when performing the interconnected operation. The interconnected reactor circuit is
Two interconnected reactors connected in series between the power converter and the power system;
2. The electric power according to claim 1, further comprising: a switching circuit that is connected in parallel to one of the two interconnected reactors connected in series and that conducts when the autonomous operation is performed. Supply system. The interconnected reactor circuit is
Two interconnected reactors connected in parallel between the power converter and the power system;
2. The electric power according to claim 1, further comprising: a switching circuit that is connected in series to one of the two interconnected reactors connected in parallel and that conducts when the autonomous operation is performed. Supply system. The interconnected reactor circuit is
A coil as the interconnected reactor,
A core made of a magnetic material and provided so as to be insertable into the coil,
The power supply system according to claim 1, wherein an insertion degree of the core portion with respect to the coil can be adjusted. The interconnected reactor circuit is
A coil as the interconnected reactor,
A contact provided to be able to contact the coil;
The power supply system according to claim 1, wherein a contact position of the contact with the coil can be adjusted. The interconnected reactor circuit is
A saturable reactor as the interconnected reactor,
The power supply system according to claim 1, further comprising an AC power supply connected to the saturable reactor and having a variable current value. A power converter;
A connected reactor circuit connected in series to the power converter and including one or more connected reactors;
The reactance of the interconnected reactor circuit in the case of performing a self-sustained operation for supplying power from the power converter to the load is supplied to the load from the power system connected to the power converter and the interconnected reactor circuit. A power conversion device, wherein the reactance of the interconnection reactor circuit when performing grid interconnection operation is smaller than the reactance.

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