WO2013047543A1

WO2013047543A1 - Power controller

Info

Publication number: WO2013047543A1
Application number: PCT/JP2012/074618
Authority: WO
Inventors: 中島　武; 中井　智通; 一男石本
Original assignee: 三洋電機株式会社
Priority date: 2011-09-28
Filing date: 2012-09-26
Publication date: 2013-04-04

Abstract

A plurality of element converters (11[1], 11[2]) for converting an input voltage (V_I) into an output voltage (V_O) by a power conversion operation is set in a power converter (11). A switching unit (12) is set up between a power line (PL) for applying an output voltage and a plurality of power input units (14[1], 14[2]). A controller (13) uses the switching unit (12) to control whether to connect the power input unit to the power line (PL) in each power input unit, and to control the number of element converters that execute the power conversion operation in response to the number of power input units connected to the power line (PL) (that is, the number of power input units that receive the power supplied by the power converter (11)).

Description

Power control device

The present invention relates to a power control apparatus that performs power input / output control.

The power system that transmits and receives power between multiple power blocks is used in various devices and facilities. In this type of power system, one or more power blocks that output power and one or more power blocks that receive power input are connected via a switching unit, and the switching unit is controlled to perform desired power transmission and transmission. Power is received (see, for example, Patent Document 1 below).

In many cases, a power block that performs power conversion operation is provided in a power block that outputs power. FIG. 8 is a schematic configuration diagram of a power system provided with a power conversion unit 911 that performs a power conversion operation. The power conversion unit 911 converts the input voltage into another voltage by the power conversion operation, and outputs the obtained other voltage as an output voltage. For example, the input voltage is an AC voltage and the output voltage is a DC voltage. A switching unit 912 is provided between a plurality of power input units (power blocks) that can receive power supply from the power conversion unit 911 and the power conversion unit 911, and the control unit 913 controls the switching unit 912. For each power input unit, it is possible to control whether or not the output voltage of the power conversion unit 911 is supplied to the power input unit.

The power conversion unit 911 outputs a current only to the power input unit connected via the switching unit 912. On the other hand, as is well known, in a power converter such as the power converter 911, the conversion efficiency depends on the output current (see FIG. 9).

JP 2010-231939 A

Therefore, in the system as shown in FIG. 8, it is difficult to always keep the conversion efficiency of the power conversion unit 911 near the maximum value.

As a simple example, let us consider a case where five power input units are provided and the current consumption of each current input unit is 10 A (ampere). In this case, assuming that the power input unit connected to the power conversion unit 911 is 1 or more, the output current of the power conversion unit 911 varies between 10A and 50A. If the power conversion unit 911 is designed so that the conversion efficiency of the power conversion unit 911 is maximized when the output current of the power conversion unit 911 is 30 A, the output current of the power conversion unit 911 is 10A, 20A, When it is 40 A or 50 A, the conversion efficiency of the power conversion unit 911 is lowered. Needless to say, it is beneficial to improve the conversion efficiency of the power converter.

Therefore, an object of the present invention is to provide a power control device that contributes to improvement of conversion efficiency in power conversion.

The power control device according to the present invention includes a power conversion unit that converts an input voltage into an output voltage, and a control unit that controls the operation of the power conversion unit. Includes a plurality of element conversion units that convert the input voltage into the output voltage, and the control unit controls whether or not to perform a conversion operation in each element conversion unit, and receives power supply from the power conversion unit The number of element conversion units that perform the conversion operation is controlled according to the number of power input units or according to the output current of the power conversion unit.

Another power control device according to the present invention is a power control device comprising: a power conversion unit that converts an input voltage into an output voltage; and a control unit that controls the operation of the power conversion unit. , Each comprising a plurality of element converters for converting the input voltage into the output voltage, the plurality of element converters include two or more element converters having different maximum output capacities, The element conversion unit controls whether or not to perform the conversion operation in the element conversion unit, and performs the conversion operation according to the required capacity of the power input unit that receives power supply from the power conversion unit. It is characterized by selecting from the part.

According to the present invention, it is possible to provide a power control apparatus that contributes to improvement in conversion efficiency in power conversion.

1 is a schematic overall configuration diagram of a power system according to a first embodiment of the present invention. It is a modified block diagram of the electric power system of FIG. It is a detailed block diagram of a part of the electric power system of FIG. It is an internal block diagram of the power converter of FIG. It is a figure which shows the structural example of the electric power system which concerns on 1st Embodiment of this invention. It is a schematic whole block diagram of the electric power system which concerns on 2nd Embodiment of this invention. It is a figure which concerns on 2nd Embodiment of this invention and shows the relationship between BSU and several electric power blocks. It is a block diagram of the conventional electric power system. It is a figure which shows the output current dependence of the conversion efficiency in a power converter device.

Hereinafter, an example of an embodiment of the present invention will be specifically described with reference to the drawings. In each of the drawings to be referred to, the same part is denoted by the same reference numeral, and redundant description regarding the same part is omitted in principle. In this specification, for simplification of description, a symbol or reference that refers to information, signal, physical quantity, state quantity, member, or the like is written to indicate information, signal, physical quantity, state quantity or Names of members and the like may be omitted or abbreviated.

<< First Embodiment >>
A first embodiment of the present invention will be described. FIG. 1 is a schematic overall configuration diagram of the power system according to the first embodiment. The power system includes all or a part of the parts shown in FIG.

An input voltage V _I is supplied to the power converter 11. The power conversion unit 11 performs power conversion for converting the input voltage V _I into an output voltage V _O different from the input voltage V _I under the control of the control unit 13, and outputs the obtained output voltage V _O to the switching unit 12. Output. As shown in FIG. 2, a switch circuit 15 formed of a semiconductor switching element or the like may be provided between the power conversion unit 11 and the switching unit 12. The input voltage V _I may be an AC voltage or a DC voltage. The output voltage V _O may also be an AC voltage or a DC voltage. In the following, as an example, an AC voltage from the commercial AC power source (not shown) is supplied to the power conversion unit 11 as the input voltage V _I, the power converter 11 converts the AC voltage as the input voltage V _I to a DC voltage Assuming that In this case, the power conversion unit 11 outputs the resulting DC voltage as the output voltage V _O.

The switching unit 12 is interposed between the power conversion unit 11 and the power input unit group 14 including a plurality of power input units, and supplies the output voltage V _O to the power input unit under the control of the control unit 13. No is switched for each power input unit. Power input unit is any site that can be powered from the power conversion unit 11, for example, the secondary battery is charged by the output power of the power conversion unit 11 (power by the output voltage V _O), or includes load driven by the output power of the power conversion unit 11 (power by the output voltage V _O). A certain power input unit includes a DC / AC inverter that converts an output voltage V _O as a DC voltage into an AC voltage and outputs the AC voltage, and an AC load that is driven by the output AC voltage of the DC / AC inverter. (AC load) may be included. In addition, a certain power input unit converts the output voltage V _O as a DC voltage into another DC voltage and outputs the other DC voltage, and the output DC voltage of the DC / DC converter It may include a DC load (direct current load) driven by.

FIG. 3 shows an example of a connection relationship between the switching unit 12 and the power input unit group 14. The m power input units forming the power input unit group 14 are referred to by reference numerals 14 [1] to 14 [m]. m is an arbitrary integer of 2 or more. Output voltage V _O from power conversion unit 11 is applied to power line PL. In this specification, the term “line” and the term “wiring” are synonymous. The switching unit 12 includes a plurality of switch circuits interposed between the power line PL and the power input unit group 14, and controls the energization state of each switch circuit under the control of the control unit 13. The connection or disconnection between the power line PL and the power input unit can be switched every time. The control unit 13 can control to switch on or off each switch circuit in the switching unit 12 for each switch circuit. A switch circuit provided between the power line PL and the power input unit 14 [i] is referred to by a symbol 12 [i] (i is an arbitrary integer). Then, the plurality of switch circuits provided in the switching unit 12 are the switch circuits 12 [1] to 12 [m]. Each of the switch circuits 12 [1] to 12 [m] can be formed by a semiconductor switching element or a mechanical relay, and the semiconductor switching element is, for example, a field-effect transistor or an insulated gate. It is a bipolar transistor (Insulated Gate Bipolar Transistor).

When the switch circuit 12 [i] is on, the power line PL and the power input unit 14 [i] are connected via the switch circuit 12 [i] and the output voltage _VO is supplied to the power input unit 14 [i]. (That is, the output power of the power conversion unit 11 is supplied to the power input unit 14 [i]). On the other hand, when the switch circuit 12 [i] is off, the power line PL and the power input unit 14 [i] are cut off by the switch circuit 12 [i] and the output voltage V _O is supplied to the power input unit 14 [i]. (That is, the output power of the power conversion unit 11 is not supplied to the power input unit 14 [i]). When the switch circuit 15 is provided as shown in FIG. 2, each switch circuit should be designed so that the rated current of the switch circuit 15 in FIG. 2 is larger than the rated current of the switch circuit 12 [i]. Is desirable.

FIG. 4 is an internal configuration diagram of the power conversion unit 11. As shown in FIG. 4, the power conversion unit 11 includes a plurality of element conversion units. The plurality of element conversion units are connected in parallel to each other. Each of the plurality of element conversion units individually converts the input voltage V _I into the output voltage V _O under the control of the control unit 13, and outputs the obtained output voltage V _O to the power line PL and the switching unit 12. be able to. By element converting unit, an operation for obtaining an output voltage V _O from the input voltage V _I, referred to as a power conversion operation (or conversion operation). The control unit 13 can control whether or not to execute the power conversion operation for each element conversion unit. A backflow suppression element (such as a diode) may be provided on the output side of each element converter so that current does not flow backward from one element converter to another element converter. In the present embodiment, for simplification of description, the voltage drop of the backflow suppressing element is ignored.

The n element conversion units forming the power conversion unit 11 are referred to by reference numerals 11 [1] to 11 [n]. n is an arbitrary integer of 2 or more. When the power conversion operation is executed in each of the element conversion units 11 [1] to 11 [n], the voltage value output from the element conversion units 11 [1] to 11 [n] is between a plurality of element conversion units. It is almost common. The element conversion unit 11 [i] converts the input voltage V _I into the output voltage V _O and outputs the output voltage V _O to the power line PL and the switching unit 12 only when the power conversion operation is performed. Therefore, if a power conversion operation is performed in the element conversion unit 11 [i] and any one or more switch circuits in the switching unit 12 are on, any one or more from the element conversion unit 11 [i]. Current supply to the power input occurs. When the power conversion operation is not performed in the element conversion unit 11 [i], no current is supplied from the element conversion unit 11 [i] to the power input unit group 14 without depending on the state of each switch circuit of the switching unit 12. .

Of the switch circuits 12 [1] to 12 [m], the number of switch circuits that are turned on is referred to as a switch-on number SW _NUM . The switch-on number SW _NUM corresponds to the number of power input units connected to the power line PL and the power conversion unit 11 via the switching unit 12 and receives power supply from the power conversion unit 11 via the switching unit 12. This corresponds to the number of power input units. That is, for example, when only the switch circuits 12 [1] and 12 [2] among the switch circuits 12 [1] to 12 [m] are on, the switch-on number SW _NUM is 2, and the power input unit 14 [ 1] to 14 [m], only the power input units 14 [1] and 14 [2] are connected to the power line PL and the power conversion unit 11 via the switching unit 12, and are connected via the switching unit 12. Power is supplied from the power converter 11. Since the control unit 13 can control switching on or off of each switch circuit of the switching unit 12 for each switch circuit, naturally, the switch-on number SW _NUM can be controlled.

Of the element conversion units 11 [1] to 11 [n], the number of element conversion units that execute the power conversion operation is referred to as a conversion ON number CON _NUM . For example, when only the element conversion unit 11 [1] is ON among the element conversion units 11 [1] to 11 [n], the conversion ON number CON _NUM is 1, and the element conversion units 11 [1] to 11 [11] Of [n], only the element conversion unit 11 [1] performs the power conversion operation. Since the control unit 13 can control whether or not to execute the power conversion operation for each element conversion unit, naturally, the conversion ON number CON _NUM can be controlled.

Then, the control unit 13 can control the conversion ON number CON _NUM according to the switch ON number SW _NUM .

Basically, for example, the control unit 13 may increase the conversion ON number CON _NUM as the switch ON number SW _NUM increases. This can be expressed as follows. Control unit 13, a transformation on the number _{CON NUM} when the switch-on number _{SW NUM} is a predetermined integer _{SW NUML,} larger than the conversion on the number _{CON NUM} when the switch-on number _{SW NUM} is a predetermined integer _{SW nums.} Here, “1 ≦ SW _NUMS <SW _NUML ” may be _satisfied , and SW _NUMS = 1 and SW _NUML = m. Note that just because the switch-on number SW _NUM increases, the control unit 13 does not always need to increase the conversion-on number CON _NUM .

Alternatively, the control unit 13 may control the conversion ON number CON _NUM according to the output current I _O of the power conversion unit 11. In this case, a current sensor (not shown) for detecting the value of the current flowing from the power conversion unit 11 to the switching unit 12 is provided in the power system, and the current value detected by the current sensor is controlled as the value of the output current _IO. Is transmitted to the unit 13.

Basically, for example, the control unit 13 may increase the conversion ON number CON _NUM as the output current _IO increases. This can be expressed as follows. Control unit 13, a transformation on the number _{CON NUM} when the value of the output current _{I O} is the predetermined value _{I L,} greater than the conversion on the number _{CON NUM} when the value of the output current _{I O} is the predetermined value _{I S} To do. Here, “I _S <I _L ”. For example, the predetermined value I _L, the actual measurement value or a design value or measured value and a value based on the design value of the current supplied from the power conversion unit 11 to the power input portion group 14 when the switch-on number SW _NUM is m there are, and, the predetermined value I _S, the actually measured value or a design value or the measured value and the design value of the current supplied from the power conversion unit 11 to the power input portion group 14 when the switch-on number SW _NUM is 1 It may be a value based on it. Incidentally, it is desirable to use the measured value of the current as the predetermined value I _L, the load and the like LED, in a case where power consumption is expected to be constant, using the design value as a predetermined value I _L problem is small (predetermined value _{I S} is similar).

As is well known, in a power conversion device such as an element conversion unit, the conversion efficiency depends on the output current (see FIG. 9). The control unit 13 may control the conversion ON number CON _NUM according to the switch ON number SW _NUM or the output current _IO so that the conversion efficiency is maximized in each element conversion unit. As a result, the conversion efficiency of the power conversion unit 11 can be kept high by adapting to the change in the current to be supplied (ideally, the conversion efficiency of the power conversion unit 11 is maximized regardless of the change in the current to be supplied. Value or maximum value).

In addition, the electric current which a power input part requires may mutually differ between several power input parts. Therefore, when controlling the conversion ON number CON _NUM according to the switch ON number SW _NUM , the control unit 13 is not only the switch ON number SW _NUM but also the power input unit connected to the power line PL via the switching unit 12. The conversion ON number CON _NUM may be determined in consideration of the current consumption (for example, the design value of the current consumption).

FIG. 5 shows the configuration of the power system when m = n = 2. The power input unit 14 [1] in FIG. 5 is a battery unit composed of one or more secondary batteries (lithium ion battery, nickel metal hydride battery, etc.), and the power input unit 14 [2] in FIG. DC load (such as a lighting fixture). When the switch circuit 12 [1] is turned on in a state where the output voltage V _O due to the power conversion operation is applied to the power line PL, the output power of the power conversion unit 11 in the power input unit 14 [1] is turned on. When the secondary battery is charged and the switch circuit 12 [2] is turned on, the DC load as the power input unit 14 [2] is driven by the output power of the power conversion unit 11. If the control unit 13 turns on the switch circuits 12 [1] and 12 [2] in a state where there is no power output of the power conversion unit 11, the discharge power of the secondary battery in the power input unit 14 [1]. It is also possible to drive a DC load as the power input unit 14 [2]. For a power system in which the discharge power of the power input unit can be used, conversion is performed according to the output current I _O rather than a method of controlling the conversion ON number CON _NUM according to the switch-on number SW _NUM. It can be said that the method of controlling the ON number CON _NUM is more suitable. In the power system in which the discharge power of the power input unit can be used, when the switch circuit 15 of FIG. 2 is provided, the control unit 13 not only switches the switch-on number SW _NUM but also the switch circuit 15. The conversion ON number CON _NUM may be controlled in accordance with the conduction state (whether it is on or off).

In the power system of FIG. 5, when only one of the switch circuits 12 [1] and 12 [2] is turned on, the control unit 13 selects one of the element conversion units 11 [1] and 11 [2]. When only one of them performs the power conversion operation and turns on both the switch circuits 12 [1] and 12 [2], the power conversion operation is performed on both of the element conversion units 11 [1] and 11 [2]. Is executed. As a simple example, a current of 10 A (ampere) flows from the power line PL to the power input unit 14 [1] when the switch circuit 11 [1] is on and 10 A (ampere) when the switch circuit 11 [2] is on. Ampere) current flows from the power line PL into the power input unit 14 [2], the conversion efficiency of the element conversion unit 11 [1] is maximized when the output current of the element conversion unit 11 [1] is 10A and If the element conversion units 11 [1] and 11 [2] are designed so that the conversion efficiency of the element conversion unit 11 [2] is maximized when the output current of the element conversion unit 11 [2] is 10A. In this way, the conversion efficiency of the power conversion unit 11 can be maintained at or near the maximum value regardless of changes in the current to be supplied.

In the power system of FIG. 5, when only one of the element conversion units 11 [1] and 11 [2] performs the power conversion operation, the control unit 13 sets the element conversion unit for executing the power conversion operation. The element conversion units 11 [1] and 11 [2] may be switched as appropriate.

For example, in the case where only one of the element conversion units 11 [1] and 11 [2] performs the power conversion operation continuously, the control unit 13 causes the power conversion operation to be performed every time a predetermined time elapses. The element conversion unit may be switched between the element conversion units 11 [1] and 11 [2].
Alternatively, for example, after the power conversion operation is executed only by the element conversion unit 11 [1] and the power conversion operation is stopped, the power conversion is performed again only to one of the element conversion units 11 [1] and 11 [2]. When the operation is performed, the control unit 13 may cause the element conversion unit 11 [2] to execute the power conversion operation (that is, the element conversion units 11 [1] and 11 [2] Alternatively, the power conversion operation may be executed).
Or, for example, an element converting unit 11 [1] total time length of performing a power conversion operation L ₁ and element converting unit 11 [2] is the total time length L ₂ of performing power conversion operation, the control unit 13 It may be measured. In this case, when to perform either only the power conversion operation of the element converting unit 11 [1] and 11 [2], the control unit 13, the difference between the total time length L ₁ and L ₂ are reduced As described above, it may be determined which of the element conversion units 11 [1] and 11 [2] is to perform the power conversion operation.

The element conversion unit 11 [i] is formed to include an electronic component (for example, an aluminum electric field capacitor) that deteriorates over time, and the deterioration of each electronic component progresses as the execution time of the power conversion operation becomes longer. In the case where only one of the element conversion units 11 [1] and 11 [2] performs the power conversion operation, the element conversion unit that executes the power conversion operation is temporarily fixed by the element conversion unit 11 [1]. Then, the deterioration of the element conversion unit 11 [1] proceeds faster than the element conversion unit 11 [2]. As described above, if the element conversion unit that performs the power conversion operation is switched between the plurality of element conversion units, the progress of deterioration is equalized between the plurality of element conversion units, and as a result, the entire power conversion unit 11 is obtained. It becomes possible to extend the lifetime of the.

The process of switching the element conversion unit for executing the power conversion operation between the plurality of element conversion units has been described for the power system of FIG. 5 (that is, the power system of m = n = 2). The present invention can also be applied to a power system corresponding to FIG. 4 (that is, a power system not limited to m = n = 2). In any case, when the control unit 13 causes only some of the element conversion units 11 [1] to 11 [n] to perform the power conversion operation, the control unit 13 performs the power conversion operation at the first timing. The element conversion unit and the element conversion unit that performs the power conversion operation at the second timing can be made different from each other. The second timing is an arbitrary timing different from the first timing. Of course, depending on the second timing (for example, when the second timing is a timing after a minute time has elapsed from the first timing), the element conversion unit that performs the power conversion operation may be common between the first and second timings. There is also.

In the power system of FIG. 1 or the like, a power output unit (not shown) that outputs power may be connected in parallel to the power conversion unit 11, and the power output unit is a solar cell unit including a solar cell. (Not shown) may be used. For example, the power output terminal of the solar cell unit is connected to the power line PL via a diode, and the solar cell unit supplies DC power based on the power generated by sunlight to the power input unit connected to the power line PL. be able to. Further, when power is supplied from both the solar cell unit and the power conversion unit 11 to the power input unit group 14, even if the power consumption of the power input unit group 14 is unchanged, the power generation of the solar cell unit is performed. The output power from the power converter 11 changes as the power changes. Therefore, the control unit 13 may change the conversion ON number CON _NUM in accordance with the generated power of the solar cell unit (in accordance with the amount of current to be output from the power conversion unit 11). In the case where the solar cell unit is provided in the power system of FIG. 1 or the like, for example, a state in which only the switch circuit 12 [1] is turned on from a state in which a plurality of switch circuits in the switching unit 12 are turned on. When the transition to, all output currents of the solar cell units that have been flowing to the plurality of power input units until now flow to the power input unit 14 [1], and overcurrent occurs in the power input unit 14 [1]. (In particular, as shown in FIG. 5, when the power input unit 14 [1] is a battery unit, the problem of overcurrent may be increased). In order to prevent this, when the above transition occurs, the control unit 13 may limit the current supplied to the power input unit 14 [1]. For example, the control unit 13 can limit the current supplied to the power input unit 14 [1] by periodically switching the state of the switch circuit 12 [1] between on and off.

Further, the maximum output capacities of the element conversion units 11 [1] to 11 [n] may be common, but the maximum of two or more element conversion units among the element conversion units 11 [1] to 11 [n]. The output capacities may be different from each other. In this case, the control unit 13 causes the power conversion operation to be performed according to the required capacity of the power input unit group 14 that receives power supply from the power conversion unit 11 so that the conversion efficiency in the power conversion unit 11 is as high as possible. One or more element conversion units may be selected from the element conversion units 11 [1] to 11 [n]. The maximum output capacity of the element converter 11 [i] is the maximum power value that can be output by the element converter 11 [i]. The required capacity of the power input unit group 14 corresponds to the value of power required by the power input unit group 14 from time to time. For example, an actual value or design value of the power, or a power value based on the actual value and the design value It is. Here, it is assumed that the maximum output capacity and the required capacity are power values, but the unit of the maximum output capacity and the required capacity may be a unit of current.

For example, the control unit 13 can recognize the necessary capacity of the power input unit group 14 based on the measurement result of a sensor (not shown) that measures the power consumption of the power input unit group 14. Alternatively, for example, the control unit 13 is based on information indicating which of the switch circuits 12 [1] to 12 [m] is turned on and a predetermined power consumption value for each power input unit. The necessary capacity of the power input unit group 14 may be recognized.

As a specific example, n = 3 and the maximum output capacities of the element conversion units 11 [1], 11 [2], and 11 [3] are 100 W, 200 W, and 400 W (watts), respectively. Consider the case. In this case, the control unit 13 causes only the element conversion unit 11 [1] to perform the power conversion operation when the required capacity of the power input unit group 14 is 80 W, and the required capacity of the power input unit group 14 is 150 W. Sometimes, it is preferable that only the element conversion unit 11 [2] perform the power conversion operation, and when the necessary capacity of the power input unit group 14 is 300 W, only the element conversion unit 11 [3] performs the power conversion operation. When the required capacity of the power input unit group 14 is 300 W, a method of stopping the element conversion unit 11 [3] while allowing the element conversion units 11 [1] and 11 [2] to perform a power conversion operation may be employed. However, the conversion efficiency when the element conversion unit is operated near the maximum output capacity is often not the most desirable conversion efficiency (see FIG. 9). Therefore, when the required capacity of the power input unit group 14 is 300 W, it is desirable that only the element conversion unit 11 [3] perform the power conversion operation. Therefore, for example, when the required capacity of the power input unit group 14 is 400 W, the control unit 13 causes only the element conversion units 11 [1] and 11 [3] to perform the power conversion operation, and the required capacity of the power input unit group 14 When 500 is 500 W, it is preferable that only the element conversion units 11 [2] and 11 [3] perform the power conversion operation. By such execution control of the power conversion operation, it is possible to keep the conversion efficiency of the power conversion unit 11 always high following the change in the required capacity of the power input unit group 14.

As shown in FIG. 9, when power conversion is performed with a low output capacity, conversion efficiency may be lower than when power conversion is performed near the maximum output capacity. On the other hand, it is preferable to perform power conversion with an output capacity that has a certain margin with respect to the maximum output capacity and has high conversion efficiency in order to be able to cope with a change in required capacity ( For example, in the vicinity of the maximum conversion efficiency in FIG. 9). Accordingly, the above-described operation example (example of the power conversion operation selection execution control) with specific numerical values regarding the capacity is merely an example, and the element conversion units that perform the power conversion operation are Not only the maximum output capacity and the required capacity of the power input unit group 14 but also the conversion efficiency characteristics of each element conversion unit (depending on the output capacity of the conversion efficiency) and the margin can vary. Thus, for example, the control unit 13 determines the value of the output capacity to be operated (for example, the conversion efficiency in FIG. (A value near the maximum) is set for each element conversion unit, and the element conversion unit that actually performs the power conversion operation is selected based on the set value and the necessary capacity of the power input unit group 14. good.

<< Second Embodiment >>
A second embodiment of the present invention will be described. FIG. 6 is a schematic overall configuration diagram of a power system according to the second embodiment.

The power system of FIG. 6 includes a battery charge / discharge control unit (hereinafter referred to as BMU (Battery Management Unit)) 31 and a battery charge / discharge switch circuit unit (hereinafter referred to as BSU (hereinafter referred to as BSU)). Battery Switching Unit) 32). In the present embodiment, the board refers to a printed board on which electronic components are mounted. As shown in FIG. 7, a plurality of power blocks PP that output power or receive power can be connected to the BSU 32, and the number of power blocks according to the number of power blocks PP to be connected to the BSU 32. The unit substrate UU can be provided in the BSU 32.

In the example of FIG. 6, three power block unit substrates UU are provided in the BSU 32 as power block unit substrates UU [1] to UU [3]. The first power block PP composed of the AC / DC converter 61A and the AC power source 61B is connected to the first power block unit substrate UU [1], and the second power block PP composed of the battery unit 62 is the second power. A third power block PP connected to the block unit substrate UU [2] and composed of the DC / DC converter 63A and the DC load 63B is connected to the third power block unit substrate UU [3].

A switch circuit, a microcomputer (hereinafter referred to as a microcomputer) and a protection circuit are mounted on each power block unit substrate UU. The switch circuit, the microcomputer, and the protection circuit in the power block unit substrate UU [i] are referred to by reference numerals 41 [i], 42 [i], and 43 [i], respectively. In each power block unit substrate UU, the microcomputer 42 [i] can control the operations of the switch circuit 41 [i] and the protection circuit 43 [i]. The switch circuit 41 [i] is the same as each switch circuit in the switching unit 12 of the first embodiment. In the configuration example of FIG. 6, the first board on which the microcomputer 42 [i] is mounted and the second board on which the switch circuit 41 [i] and the protection circuit 43 [i] are mounted are separated. A combination of the second substrates is called a power block unit substrate UU [i]. Note that the first and second substrates may be combined into one substrate.

The BSU32, so that the power line _{P BUS} is common bus line to the power block unit substrate UU [1] ~ UU [3 ], transverse to the power block substrate UU [1] ~ UU [3 ] The power block unit substrates UU [1] to UU [3] are connected to each other through at least the power line _PBUS . The power line _PBUS includes a negative power line having a negative potential and a positive power line having a positive potential.

The AC power source 61B is a power source that outputs AC power having a predetermined voltage value and frequency. The AC power source 61B may be a commercial AC power source. The AC / DC converter 61A converts the AC voltage from the AC power source 61B into a DC voltage, and outputs the DC voltage from its output terminal T [1]. The switch circuit 41 [1] is interposed in series between the power line _PBUS and the output terminal T [1] of the AC / DC converter 61A. Only when the switch circuit 41 [1] is ON, the output DC voltage of the AC / DC converter 61A is applied to the power line _PBUS (more specifically, the negative power line and the positive power that form the power line _PBUS). When the switch circuit 41 [1] is off, the AC / DC converter 61A is disconnected from the power line _PBUS .

The switch circuit 41 [2] is interposed in series between the power line _PBUS and the input / output terminal T [2] of the battery unit 62. The switch circuit 41 [2] when on only input and output terminals T of the battery unit 62 [2] is connected to the power line _{P BUS,} it is possible to charge or discharge of the battery 62 via the power line _{P BUS} .

Switching circuit 41 [3] is interposed in series between the input terminal T of the power line _{P BUS} and the DC / DC converter 63A [3]. Only when the switch circuit 41 [3] is on, the DC voltage applied to the power line _PBUS is applied to the input terminal T [3]. When the switch circuit 41 [3] is off, the DC / DC converter 63A _Disconnected from line _PBUS . The DC / DC converter 63A converts the DC voltage applied to the input terminal T [3] into another DC voltage, and outputs the other DC voltage to the DC load 63B. The DC load 63B is a DC load that is driven using the output DC voltage of the DC / DC converter 63A as a drive voltage.

In the power block unit substrate UU [i] (i is an arbitrary integer), the microcomputer 42 [i] performs on / off switching control of the switch circuit 41 [i], and the protection circuit 43 [i] generates an abnormality. At the time (for example, when the switch circuit 41 [i] abnormally generates heat), the switch circuit 41 [i] is forcibly turned off.

Communication is possible between the microcomputers 42 [1] and 42 [2] adjacent to each other, communication is possible between the microcomputers 42 [2] and 42 [3] adjacent to each other, and the microcomputer 42 [3]. And BMU 31 can communicate with each other. Thereby, communication is possible between the arbitrary microcomputer 42 [i] and the BMU 31. However, as long as communication is possible between any microcomputer 42 [i] and the BMU 31, the connection methods of the microcomputers 42 [1] to 42 [3] and the BMU 31 are arbitrary. The BMU 31 can output various commands to the microcomputers 42 [1] to 42 [3] using the communication with the microcomputers 42 [1] to 42 [3], and thereby the switch circuits 41 [1] to 42 [3]. It is also possible to control on or off of 41 [3].

The technique described in the first embodiment can be applied to the power system of FIG. In this application, the switch circuit 41 [1], the switch circuit 41 [2], the switch circuit 41 [3], and the power line _PBUS are respectively connected to the switch circuit 15, the switch circuit 12 [1], The battery unit 62 is regarded as the power input unit 14 [1] of the first embodiment, and the DC / DC converter 63A and the DC load 63B are further regarded as the switch circuit 12 [2] and the power line PL. What is necessary is just to consider it as the electric power input part 14 [2] (refer FIG.2 and FIG.5). In addition, the power converter 11 of the first embodiment can be used as the AC / DC converter 61A. The BMU 31 can control the conversion ON number CON _NUM according to the method described in the first embodiment, and can perform a process of switching an element conversion unit that executes a power conversion operation among a plurality of element conversion units. . In the configuration example of FIG. 6, it can be said that a combination of the BMU 31 and the microcomputers 42 [1] to 42 [3] functions as the control unit 13 of the first embodiment, and the switch circuits 41 [2] and 41 [ 3] can be said to function as the switching unit 12 of the first embodiment.

In the power system of FIG. 6, power transmission and power reception are performed between three power blocks PP, but the BSU 32 may be formed so that power transmission and power reception is performed between four or more power blocks PP. Also in this case, the conversion ON number CON _{NUM and the} like can be controlled according to the method described in the first embodiment.

When transmitting and receiving power between a plurality of power blocks PP, in the conventional system, it is necessary to develop and create a dedicated board for the system according to the system configuration. According to the power system according to the present embodiment, however, Thus, development and creation of a dedicated board for each system is not necessary. A dedicated board is prepared by arranging the required number of power block unit boards UU in the BSU 32 according to the number of power blocks PP that transmit or receive power and centrally manage the operations in each power block unit board UU with the BMU 31. The same effect as that obtained can be obtained. If the power block unit substrate UU provided in the BSU 32 is shared, it is expected that the substrate development time can be reduced and the maintainability can be improved. In addition, when it is desired to add a new power block PP after forming the power system once, the new power block PP can be incorporated into the power system simply by adding the power block unit board UU to the BSU 32. That is, the power system of this embodiment has high expandability. Normally, when the power system is expanded or the like, the load amount or the like changes. However, by performing the above-described execution control of the power conversion operation, it is possible to maintain high conversion efficiency even after the expansion.

<< Deformation, etc. >>
The embodiment of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims. The above embodiment is merely an example of the embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the above embodiment. The specific numerical values shown in the above description are merely examples, and as a matter of course, they can be changed to various numerical values. As annotation items applicable to the above-described embodiment, annotations 1 to 4 are described below. The contents described in each comment can be arbitrarily combined as long as there is no contradiction.

[Note 1]
In the power system shown in FIG. 1 and the like, the control unit 13 is provided outside the power conversion unit 11, but the control unit 13 may be provided in the power conversion unit 11.

[Note 2]
It can be considered that the power system of each of the embodiments described above functions as a power control device or includes the power control device.

[Note 3]
A mobile body (an electric vehicle, a ship, an aircraft, an elevator, a walking robot, etc.) or an electronic device that drives the power system or power control device of each embodiment described above using the output power of the power converter 11 or the AC / DC converter 61A You may mount in apparatus (a personal computer, a portable terminal, etc.), and you may incorporate in the electric power system of a house or a factory.

[Note 4]
You may implement | achieve all or one part of the function implement | achieved with the electric power system or electric power control apparatus of each above-mentioned embodiment using software. A function realized using software may be described as a program, and the function may be realized by executing the program on a program execution device (for example, a computer).

DESCRIPTION OF SYMBOLS 11 Power conversion part 11 [1] -11 [n] Element conversion part 12 Switching part 12 [1] -12 [m] Switch circuit 13 Control part 14 Power input part group 14 [1] -14 [m] Power input part 15 Switch circuit PL Power line

Claims

A power converter that converts input voltage to output voltage;
In a power control device comprising a control unit that controls the operation of the power conversion unit,
The power conversion unit includes a plurality of element conversion units each converting the input voltage to the output voltage,
The control unit controls whether to perform a conversion operation in each element conversion unit, and according to the number of power input units that receive power supply from the power conversion unit or according to the output current of the power conversion unit A power control apparatus that controls the number of the element conversion units that execute the conversion operation.
When the control unit causes only a part of the plurality of element conversion units to perform the conversion operation at each of a first timing and a second timing different from the first timing, The power control apparatus according to claim 1, wherein an element conversion unit that performs the conversion operation at a timing and an element conversion unit that performs the conversion operation at the second timing are different from each other.
A power line to which the output voltage from the power converter is applied;
A switching unit interposed between the power line and a plurality of power input units, and connected or cut off between the power line and each power input unit under the control of the control unit,
The power control apparatus according to claim 1 or 2, wherein the number is the number of the power input units connected to the power line via the switching unit.
A power converter that converts input voltage to output voltage;
In a power control device comprising a control unit that controls the operation of the power conversion unit,
The power conversion unit includes a plurality of element conversion units each converting the input voltage to the output voltage,
The plurality of element converters include two or more element converters having different maximum output capacities,
The control unit controls whether or not to execute a conversion operation in each element conversion unit, and performs the conversion operation according to a required capacity of a power input unit that receives power supply from the power conversion unit Is selected from the plurality of element conversion units.