JP5596521B2 - DC power supply system and bidirectional power converter - Google Patents

Description

  The present invention relates to a DC power supply system that converts an AC voltage supplied from an AC power system into a DC voltage and outputs the DC voltage to an external load, and a bidirectional power converter used in the DC power supply system.

  In recent years, in an information communication system constructed in a data center or a communication building, power consumption has increased with an increase in information communication devices used. Therefore, from the viewpoint of global environmental problems, it is required to reduce power consumption in the information communication system.

  In order to reduce power consumption in such an information communication system, an AC voltage supplied from an AC power system such as a commercial power source is converted into a DC voltage by a rectifier and output to various information communication devices that are external loads. DC power supply systems are attracting attention. Further, in this DC power supply system, there has been a movement to increase the output voltage to a high voltage (for example, DC 380V) for higher efficiency.

  In this type of DC power supply system, conventionally, a storage battery and this storage battery are used as a backup when an abnormality such as a system fault occurs in the AC power system and a predetermined DC voltage cannot be normally output from the rectifier. And a charging device for charging the storage battery with power supplied from the AC power system or the rectifier. A more specific configuration example is shown in FIG.

  A conventional DC power supply system 120 shown in FIG. 4 includes a rectifier 2 that converts a three-phase alternating current (AC) input voltage (for example, AC 200 V) from an alternating current power system into a DC voltage having a predetermined voltage value (for example, direct current 380 V); The positive and negative power supply lines 9 and 10 for supplying the DC voltage from the rectifier 2 to the external load 3, the storage battery 5, and the AC input from the AC power system for charging the storage battery 5 The charging device 4 that converts the voltage into a DC voltage for charging and supplies it to the storage battery 5 and the power supply from the storage battery 5 when a predetermined DC voltage is not normally output from the rectifier 2 due to a system fault or the like The voltage compensator 121 for outputting a DC voltage to the power supply lines 9 and 10 and the voltage compensator 121 are operated so that the output voltage becomes a predetermined DC voltage (for example, 380 V described above). And Gosuru control unit 122, and a. The DC voltage output from the voltage compensator 121 is output to the power supply lines 9 and 10 via the backflow preventing OR diode D1.

  The voltage compensator 122 includes an inductor L11 having one end connected to the positive electrode of the storage battery 5, and a semiconductor switch (eg, MOSFET, hereinafter referred to as “switch”) having a drain connected to the other end of the inductor L11 and a source connected to the negative electrode of the storage battery 5. 103), a capacitor C11 having one end connected to one end of the inductor L11 and the other end connected to the anode of the OR diode D1, and an anode connected to the drain of the switch 103 and a cathode connected to the anode of the OR diode D1. And the control unit 122 controls the switching operation (ON / OFF operation) of the switch 103 to convert the voltage of the storage battery 5 into a predetermined DC voltage, thereby supplying the power supply line. 9 and 10.

  The voltage compensator 122 does not always operate at the time of a system failure or the like, and the voltage of the storage battery 5 is a sufficient value (for example, 380 V described above), and the voltage can be output to the power supply lines 9 and 10 as they are. In this case, the voltage compensator 122 does not operate. Therefore, in this case, the voltage of the storage battery 5 is output to the power supply lines 9 and 10 via the bypass diode D2 provided on the energization path from the positive electrode of the storage battery 5 to the power supply line 9 on the positive electrode side. It becomes.

  By the way, the conventional DC power supply system 120 illustrated in FIG. 4 has two power converters (the rectifier 2 and the charging device 4) for converting an AC input voltage into a DC voltage, and the voltage of the storage battery 5 is set to a predetermined value. A power converter (voltage compensator 121) for converting to a DC voltage is included, and each of these power converters occupies a considerable size in the system 120.

  Furthermore, in an actual DC power supply system, there are a plurality of external loads, and for each load, a system composed of a rectifier, a storage battery, a charging device, and a voltage compensation device (ie, the DC power supply system shown in FIG. 4) is constructed. In such a case, the number of power converters increases as the number of loads increases.

  A more specific example is a DC power supply system 100 as shown in FIG. The DC power supply system 100 includes a first load 101-1, a second load 101-2, a third load 101-3,..., An Nth load 101-N as external loads. Each includes a rectifier for supplying a DC voltage to the load. That is, a DC voltage is supplied from the first rectifier 102-1 to the first load 101-1 via the power supply line 111-1, and the second rectifier 102 is supplied to the second load 101-2. -2 is supplied with the DC voltage via the power supply line 111-2, and the third load 101-3 is supplied with the DC voltage from the third rectifier 102-3 via the power supply line 111-3. The DC voltage is supplied to the Nth load 101-N from the Nth rectifier 102-N through the power supply line 111-N.

  Further, the storage batteries (first storage battery 103-1, second storage battery 103-2, third storage battery 103-3,..., Nth storage battery 103-N) and these storage batteries are charged individually for each load. Charging devices (first charging device 106-1, second charging device 106-2, third charging device 106-3,..., Nth charging device 106-N) and external loads corresponding to the voltages of these storage batteries Voltage compensators (first voltage compensator 104-1, second voltage compensator 104-2, third voltage compensator 104-3,..., Which are converted into operating DC voltage and output to the corresponding power supply line N-th voltage compensation device 104-N) and control units (first control unit 105-1, second control unit 105-2, third control unit 105-3,. .., N-th control unit 105-N).

  Furthermore, each control unit respectively has a corresponding rectifier and an external load and a communication line (first communication line 115-1, second communication line 115-2, third communication line 115-3,..., Nth Information can be transmitted / received via the communication line 115-N), information on the operating state of the corresponding rectifier and the power consumption of the load is acquired, and the corresponding voltage compensator is based on the acquired information To control the operation.

  In the DC power supply system 100 configured as described above, the DC power supply system 120 shown in FIG. 4 is constructed for each of a plurality of loads, and the number of power converters increases as the number of loads increases. As a result, the DC power supply system 100 as a whole is increased in scale and cost.

  Therefore, in order to realize and popularize a DC power supply system, it is necessary to further improve the efficiency of the system (improvement of power conversion efficiency, simplification of device configuration, cost reduction, etc.). It is essential to review the configuration of power converters and to examine the functions required of power converters.

  As a technique for efficiently constructing a power converter and realizing cost and installation space saving, a single step-down circuit is provided and voltage input / output to the step-down circuit can be switched by a switching circuit. The battery operates in either a charge mode where the voltage from the DC power supply for load operation is stepped down by the step-down circuit and supplied to the assembled battery, or a discharge mode where the voltage from the assembled battery is stepped down by the step-down circuit and supplied to the load A bidirectional converter that can be made is proposed (see, for example, Patent Document 1).

JP 2009-171724 A

  However, the bidirectional converter proposed in Patent Document 1 is configured to perform power conversion using a step-down circuit, and when charging an assembled battery, the voltage from the DC power source is stepped down by the step-down circuit and used for charging. In addition to generating voltage, the voltage of the assembled battery is stepped down by the step-down circuit and supplied to the load even when power is supplied from the assembled battery to the load, so the cases where this bidirectional converter can be applied are naturally limited. End up.

  In other words, the bidirectional converter as disclosed in Patent Document 1 can be applied to a voltage lower than the voltage supplied from the DC power supply during normal operation by the external load (specifically, a voltage lower than the voltage of the assembled battery). However, it is limited to a conditional system such as a case where it is configured to be operable. Therefore, for a system that needs to supply a voltage higher than the voltage of the assembled battery (storage battery) to the load, for example, a DC power supply system as illustrated in FIG. You can't use a bidirectional converter like that.

  Therefore, it is desired to realize further simplification of the configuration of the entire system and cost reduction for the DC power supply system as illustrated in FIG. 4 without impairing the function of the system.

  The present invention has been made in view of the above problems, and an object thereof is to achieve further simplification of the configuration and cost reduction of a DC power supply system including a backup storage battery and a voltage compensation device.

  The invention according to claim 1, which has been made in order to solve the above-described problems, includes a rectifier that converts an AC voltage input from an AC power system into a DC voltage and outputs the DC voltage to a power supply line to an external load, a storage battery, And a bi-directional power conversion device provided between the power supply line and the storage battery. The bidirectional power conversion device includes a power conversion circuit and a control unit.

  Among them, the power conversion circuit steps down the DC voltage from the rectifier input from the power supply line and supplies it to the storage battery to charge the storage battery, and boosts the voltage of the storage battery to increase the power supply line. Output voltage to the external load by supplying power to the external load.

  The control means operates the power conversion circuit with the storage battery charging function when the rectifying device can normally output the DC voltage, and when the rectifying device cannot output the DC voltage normally, the power converting circuit functions as a load voltage compensation function. Operate with.

  In the DC power supply system according to claim 1 configured as described above, the power conversion circuit includes a storage battery charging function (stepping down a DC voltage from the rectifier and outputting it to the storage battery) and a load voltage compensation function (the storage battery voltage). The voltage is boosted and output to the power supply line), and bidirectional power conversion is possible.

  With such a configuration, in the present invention, when the rectifier cannot normally output a DC voltage, the power converter circuit operates with a load voltage compensation function so that the power converter circuit outputs a DC voltage to the external load instead of the rectifier. Supply. That is, it operates in the same manner as a conventional voltage compensator (see FIG. 4).

  The conventional voltage compensation device basically does not operate when the rectifier can normally output a DC voltage, whereas the power conversion circuit of the present invention is a load voltage compensation function. In addition to the operation (that is, the same operation as the voltage compensation device), when the rectifier can normally output a DC voltage, it operates as a storage battery charging function. Supply.

  This eliminates the need to provide a separate charging device for charging the storage battery by generating a DC voltage for charging the storage battery from the AC voltage as in the past, and further simplifies the configuration and reduces costs of the DC power supply system. It becomes possible to do. Moreover, since one power conversion circuit can operate with the above two functions, the utilization (operation) efficiency of the device (circuit) can be improved as compared with the conventional voltage compensation device.

  Note that “normal” for the DC voltage output from the rectifier means that the external load can be operated by the DC voltage, and therefore the DC voltage cannot be output normally. That is, it means a time when the external load cannot be operated normally with the DC voltage from the rectifier. Therefore, in such a case, the control means operates the power conversion circuit with the load voltage compensation function.

DC power supply system according to 請 Motomeko 1, further bidirectional power conversion device has a structure having a main diode and a main switch. Among these, the main diode is provided on the energization path between the power conversion circuit and the power supply line, permits energization from the power conversion circuit to the power supply line, and prevents energization in the opposite direction. The main switch is connected in parallel with the main diode, and enables the energization from the power supply line to the power conversion circuit by short-circuiting both ends of the main diode.

  When the rectifier can normally output the DC voltage, the control means closes the main switch to short-circuit both ends of the main diode and operates the power conversion circuit with the storage battery charging function. When normal output is not possible, the main switch is opened and the power conversion circuit is operated with the load voltage compensation function.

  According to the DC power supply system configured as described above, since the main switch is provided in parallel with the main diode, when operating in the storage battery charging function, the main switch is closed and the rectifier is connected via the main switch. The DC voltage can be input to the power conversion circuit, whereby the storage battery can be charged.

  On the other hand, during operation with the load voltage compensation function, the DC voltage from the power conversion circuit is output to the power supply line while preventing the inflow of power from the power supply line side to the power conversion circuit by opening the main switch. External load can be operated. Therefore, it becomes possible to provide a DC power supply system with higher reliability.

Here, more specifically, the power conversion circuit can be configured as described in claim 2 , for example. That is, the power conversion circuit includes a step-down circuit unit that realizes a storage battery charging function and a step-up circuit unit that realizes a load voltage compensation function.

  The boost circuit unit includes at least an inductor having one end connected to the positive electrode side of the storage battery, a first switch having one end connected to the negative electrode side of the storage battery and the other end connected to the other end side of the inductor, And a first diode having an anode connected to a connection point of the first switch. The step-down circuit unit includes at least a second switch that is connected in parallel to the first diode and short-circuits both ends of the first diode, thereby enabling energization from the cathode side to the anode side of the first diode. And a second diode having an anode connected to one end of the first switch and a cathode connected to the other end of the first switch, and the inductor.

  Then, when operating the power conversion circuit with the load voltage compensation function, the control means opens the second switch and controls the opening and closing of the first switch to operate the boost circuit unit to boost the voltage of the storage battery. When the power conversion circuit is operated with the storage battery charging function, the step-down circuit unit is operated by opening and closing the first switch and controlling the opening and closing of the second switch to step down the DC voltage input from the power supply line. .

  In the DC power supply system configured as described above, the power conversion circuit configuring the bidirectional power conversion device includes a step-down circuit unit and a step-up circuit unit, and among the components of each circuit unit, As for the inductor that plays the main role for boosting, the same inductor is shared by both the step-down circuit unit and the step-up circuit unit.

In other words, the step-down circuit unit and the step-up circuit unit are configured so that the same inductor can be shared by both step-down and step-up.
Therefore, according to the DC power supply system having the above configuration, the configuration of the power conversion circuit can be further simplified, and the configuration of the entire system can be further simplified and the cost can be reduced.

Next, the invention according to claim 3 is the DC power supply system according to claim 1 or 2 , wherein the rectifier includes a plurality of external loads and a power supply line for each external load. Is supplied in parallel to each external load via each power supply line. For each external load, a bidirectional power converter is connected to a power supply line corresponding to the external load.

  According to the DC power supply system configured as described above, since the bidirectional power conversion device is provided for each external load, the storage device is provided for each storage battery as in the related art, although the storage battery is provided for each external load. The charging of the storage battery can be realized by operating the power conversion circuit with the storage battery charging function. Therefore, even if the number of external loads is large (that is, the number of storage batteries is large), the increase in the scale of the entire system can be kept low.

  Moreover, since power is supplied in parallel from the rectifier to a plurality of external loads and a bidirectional power converter is provided for each external load, the output voltage from each bidirectional power converter is supplied to the corresponding external load. Of course, it is possible to supply to other external loads other than the corresponding external load.

  For this reason, for example, by controlling the operation of each bidirectional power conversion device (that is, the operation of the power conversion circuit) based on the information on the power consumption of each external load and the charge capacity of each storage battery, it corresponds to any external load. Even if the storage battery has insufficient capacity and the external battery cannot be operated depending on the storage battery, any other bidirectional power conversion device (both corresponding to any other external load) The external load can be operated by receiving power supply from the power converter.

  In other words, the bidirectional power converter provided corresponding to each external load is basically for operating the external load corresponding to itself, but the state of the entire system (capacity of each storage battery and each Depending on the power consumption of the external load, it can be supplied to other external loads in parallel.

Next, the invention according to claim 4 is a bidirectional power conversion device including a power conversion circuit, a main diode, a main switch, and a control means.
The power conversion circuit has a first input / output terminal connected to an external power supply line and a second input / output terminal connected to a storage battery, and is input from the power supply line to the first input / output terminal. A storage battery charging function for charging the storage battery by stepping down a DC voltage and outputting it from the second input / output terminal, and a first input / output terminal by boosting the voltage of the storage battery input from the second input / output terminal Has a power supply function for outputting to the power supply line.

  The main diode is provided on the energization path between the first input / output end and the power supply line, and energization from the first input / output end to the power supply line is permitted. The main switch is connected in parallel with the main diode, and enables the energization from the power supply line to the first input / output terminal by short-circuiting both ends of the main diode.

  When the first predetermined condition is satisfied, the control means closes the main switch to short-circuit both ends of the main diode, operates the power conversion circuit with the storage battery charging function, and sets the predetermined first When the condition 2 is satisfied, the main switch is opened and the power conversion circuit is operated with the power supply function.

According to the bidirectional power converter configured as described above, the DC power supply system according to claim 1 can be constructed, and in this case, the same effect as that of claim 1 can be obtained.

It is a lineblock diagram showing a schematic structure of a direct-current power supply system of a 1st embodiment. It is explanatory drawing for demonstrating operation | movement of the DC power supply system of 1st Embodiment. It is a block diagram showing schematic structure of the DC power supply system of 2nd Embodiment. It is a block diagram showing schematic structure of the conventional DC power supply system. It is a block diagram showing schematic structure of the conventional DC power supply system.

Preferred embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 shows a schematic configuration of a DC power supply system 100 of the present embodiment. In the DC power supply system 100 in FIG. 1, the same components as those in the conventional DC power supply system 120 shown in FIG.

  The DC power supply system 100 according to the present embodiment includes a rectifier 2 that converts a three-phase alternating current (AC) input voltage (for example, AC 200 V) from an AC power system into a DC voltage having a predetermined voltage value (for example, direct current 380 V), and this rectification. The positive and negative power supply lines 9 and 10 for supplying the DC voltage from the device 2 to the external load 3, the storage battery 5, the function of charging the storage battery 5 and the power of the storage battery are supplied to the external load 3. A bidirectional power conversion circuit 6 having a function to perform the operation, an input / output switching unit 7 provided on an energization path between the bidirectional power conversion circuit 6 and the power supply line 9, a bidirectional power conversion circuit 6 and an input And a control unit 8 that controls the operation of the output switching unit 7.

  In addition to the basic function of converting an AC input voltage into a DC voltage and outputting the DC voltage, the rectifier 2 is supplied to the power supply lines 9 and 10 due to an AC power system abnormality such as a power failure or an abnormality of the rectifier 2 itself. When the DC voltage required for the operation cannot be normally output to the external load 3 (hereinafter also referred to as “rectified output abnormal state”), a power failure detection signal indicating that is output to the control unit 8. . On the contrary, after the rectification output abnormal state is entered and the power failure detection signal is output, the rectification device 2 is in a normal state from the abnormal rectification output state (a state in which the DC voltage for operation can be normally output to the external load 3). Even in this case, a return signal indicating that is output to the control unit 8.

  The storage battery 5 has a positive electrode connected to the positive power supply line 9 via the bypass diode D2, and a negative electrode connected to the negative power supply line 10. The bypass diode D2 has an anode connected to the positive electrode of the storage battery 5 and a cathode connected to the power supply lines 9 and 10 on the positive electrode side, whereby the voltage of the storage battery 5 is supplied via the bypass diode D2. Output to the supply lines 9 and 10 is possible.

  Further, the positive electrode and the negative electrode of the storage battery 5 are also connected to the bidirectional power conversion circuit 6, and the voltage of the storage battery 5 can be input to the bidirectional power conversion circuit 6 and charging from the bidirectional power conversion circuit 6 is performed. DC voltage can be output to the storage battery 5.

  The bidirectional power conversion circuit 6 steps down the DC voltage from the rectifier 2 input from the power supply lines 9 and 10 and supplies the storage battery 5 by charging the storage battery 5 and the voltage of the storage battery 5. Is converted (boosted in this example) and output to the power supply lines 9 and 10 to have a load voltage compensation function for supplying the power of the storage battery 5 to the external load 3.

  That is, the bidirectional power conversion circuit 6 includes an inductor L1 having one end connected to the positive electrode of the storage battery 5 and a first semiconductor switch having a drain connected to the other end of the inductor L1 and a source connected to the negative electrode of the storage battery 5. (For example, MOSFET, hereinafter referred to as “first switch”) 11, a capacitor C 1 having one end connected to one end of the inductor L 1 and the other end connected to the anode of the OR diode D 1, and the anode being the drain of the first switch 11 And a cathode connected to the other end of the capacitor C1, a drain connected to the cathode of the first diode D3, and a source connected to the anode of the first diode D3 (ie, the first diode). A second semiconductor switch (eg, MOSFET, hereinafter referred to as a “second switch”) 12 connected in parallel to D3; Node includes a second diode D4 whose cathode is connected to the source of the first switch 11 is connected to the drain of the first switch, the.

  The bidirectional power conversion circuit 6 configured as described above is considered to be a circuit in which a step-down circuit unit for realizing a storage battery charging function and a step-up circuit unit for realizing a load voltage compensation function are mixed in terms of functions. be able to. That is, a booster circuit unit for realizing the load voltage compensation function is configured mainly by the inductor L1, the first switch 11, and the first diode D3, and mainly by the inductor L1, the second switch 12, and the second diode D4. A step-down circuit unit for realizing the storage battery charging function is configured. That is, the inductor L1 is shared by both the step-down circuit unit and the step-up circuit unit.

  The on / off (open / close) of the first switch 11 is controlled by a first switch control signal S1 (high level or low level) input from the control unit 8 to the gate of the first switch 11, and the second switch 12 ON / OFF (open / close) is controlled by a second switch control signal S2 (high level or low level) input from the control unit 8 to the gate of the second switch 12.

  Of the input / output terminals of the bidirectional power conversion circuit 6, one input / output terminal (the cathode side of the first diode, which corresponds to the first input / output terminal of the present invention) and the power supply line 9 on the positive electrode side An input / output switching unit 7 is provided on the energization path therebetween. The other input / output end (one end side of the inductor L1; corresponding to the second input / output end of the present invention) of both input / output ends of the bidirectional power conversion circuit 6 is connected to the positive electrode of the storage battery 5. Yes.

  The input / output switching unit 7 includes an OR diode D1 whose anode is connected to one input / output terminal of the bidirectional power conversion circuit 6 and whose cathode is connected to the positive power supply line 9, and whose source is the anode of the OR diode D1. And a third semiconductor switch (for example, MOSFET, hereinafter referred to as “mode changeover switch”) having a drain connected to the cathode of the OR diode D1. On / off (open / close) of the mode switch 13 is controlled by a third switch control signal S3 (high level or low level) input from the controller 8 to the gate of the mode switch 13.

  By including the input / output switching unit 7 configured as described above, the OR diode D1 connects the bidirectional power conversion circuit 6 to the power supply lines 9, 10 while the mode switch 13 is off. Although energization is permitted, energization in the opposite direction (from the power supply lines 9 and 10 to the bidirectional power conversion circuit 6) is blocked. On the other hand, while the mode changeover switch 13 is on, both ends of the OR diode D1 are short-circuited by the mode changeover switch 13, so that power is supplied from the power supply lines 9 and 10 to the bidirectional power conversion circuit 6. Is possible.

  Based on the power failure detection signal and the return signal from the rectifier 2, the control unit 8 changes the operation mode of the bidirectional power conversion circuit 6 and the input / output switching unit 7 to either the storage battery charging mode or the load voltage compensation mode. Switch.

  During normal operation in which the rectifying device 2 normally outputs a DC voltage, the AC input voltage (200 V) is converted to DC 380 V (AC / DC conversion) by the rectifying device 2 and output to the external load 3 side. In this case, the control unit 8 is operated in the storage battery charging mode.

  That is, the mode changeover switch 13 of the input / output switching unit 7 is turned on to short-circuit both ends of the OR diode D1, and the bidirectional power conversion circuit 6 is operated with the storage battery charging function. Specifically, by turning off (opening) the first switch 11 and controlling the switching operation (on / off operation) of the second switch 12 (for example, duty control), the above-described step-down circuit unit is operated, The DC voltage input from the rectifier 2 through the power supply lines 9 and 10 is stepped down to a charging DC voltage and output to the storage battery 5.

  On the other hand, when a rectification output abnormal state in which the DC voltage cannot be normally output from the rectifier 2, a power failure detection signal is output from the rectifier 2 to the control unit 8, so that the control unit 8 receives the power failure detection signal. Then, it is operated in the load voltage compensation mode.

  That is, the mode changeover switch 13 of the input / output switching unit 7 is turned off, and the bidirectional power conversion circuit 6 is operated by the load voltage compensation function. Specifically, by turning off (opening) the second switch 12 and controlling the switching operation (on / off operation) of the second switch 12 (for example, duty control), the boosting circuit unit described above is operated, The voltage of the storage battery 5 is boosted to a voltage value (380 V) equivalent to the DC voltage output from the rectifying device 2 during normal operation of the rectifying device 2. Then, the boosted DC voltage is output to the power supply lines 9 and 10 via the OR diode D1.

  Thus, even when a predetermined DC voltage cannot be supplied from the rectifier 2 to the external load 3, the operation of the external load 3 can be continued by the DC voltage supplied from the bidirectional power conversion circuit 6.

  If the voltage of the storage battery 5 is already a voltage value that allows the external load 3 to operate normally, there is no need to further boost the voltage, so the control unit 8 operates the bidirectional power conversion circuit 6. Stop. In this case, the voltage of the storage battery 5 is output to the power supply lines 9 and 10 via the bypass diode D2.

  When the rectifying device 2 returns to the normal state again, a return signal is output from the rectifying device 2 to the control unit 8, so that the control unit 8 receives the return signal and enters the storage battery charging mode again. Make it work.

  As is apparent from the comparison between the voltage compensator 121 in the conventional DC power supply system 120 shown in FIG. 4, the bidirectional power conversion circuit 6 has a second switch 12 and a second diode D4. Is added.

  In other words, the conventional voltage compensator 121 has only a load voltage compensation function for boosting the voltage of the storage battery 5 and supplying it to an external load, and was basically not operating during normal operation of the rectifier 2. On the other hand, by constructing as a bidirectional power conversion circuit having a storage battery charging function by adding components as described above, the battery 5 is charged even when the rectifier 2 is operating normally. Yes.

  FIG. 2 shows an operation example of the DC power supply system 1 of the present embodiment. 2A shows an example of changes in the output voltage (DC voltage) and load voltage (voltage input to the external load 3) of the rectifier 2, and FIG. 2B shows battery voltage (voltage of the storage battery 5). ), And FIG. 2C shows an example of change in the inductor current (current flowing through the inductor L1). In FIG. 2A, the solid line indicates the load voltage, and the broken line indicates the output voltage of the rectifier 2.

  As shown in FIG. 2A, while the rectifier 2 is operating normally (0 to about 2.2 ms), the output voltage (about 380 V) from the rectifier 2 is input to the external load 3 as it is. The During this time, the operation mode is set to the storage battery charging mode, and the bidirectional power conversion circuit 6 operates with the storage battery charging function, so that the storage battery 5 is charged. In this example, the charging voltage of the storage battery 5 is set to about 260 V (see FIG. 2B), and the output from the bidirectional power conversion circuit 6 to the storage battery 5 so that the voltage of the storage battery 5 is about 260 V. Voltage and output current are controlled. Further, according to the charging operation, a current also flows through the inductor L1 (see FIG. 2C).

  Then, when the rectified output is abnormal due to a power failure or the like, and the output voltage from the rectifying device 2 decreases to a predetermined threshold value Vr (for example, 360 V) or less as shown in FIG. The mode is switched, and the bidirectional power conversion circuit 6 starts the operation with the load voltage compensation function. That is, the voltage of the storage battery 5 is boosted and output to the external load 3, whereby the voltage input to the external load 3 is maintained at a level at which the external load 3 can operate normally. At this time, a large current (discharge current) accompanying the step-up operation flows through the inductor L1 (see FIG. 2C). In this case, since the charging power of the storage battery 5 is supplied to the external load 3, the charging power of the storage battery 5 gradually decreases (see FIG. 2B).

  The threshold value Vr for operating the bidirectional power conversion circuit 6 in the load voltage compensation mode is as long as the normal operation of the external load 3 can be maintained even if the output voltage from the rectifying device 2 decreases. It can be set appropriately.

  When an abnormality such as a power failure is resolved and the rectifier 2 operates normally again (about 12.5 ms), the output voltage from the rectifier 2 is a normal value (as shown in FIG. 2A). 380V). In this case, the operation mode is again switched to the storage battery charging mode, and the bidirectional power conversion circuit 6 operates with the storage battery charging function, so that a current accompanying the charging operation flows through the inductor L1 (FIG. 2 (c)). reference). In addition, the voltage of the storage battery 5 gradually increases by the charging operation (see FIG. 2B).

  In the present embodiment, the control unit 8 is configured to switch the operation mode based on the signals (the power failure detection signal and the return signal) from the rectifying device 2, but such a configuration is an example, As long as the operation mode can be appropriately switched depending on whether or not the DC voltage can be normally output from the device 2, there is no particular limitation on what the control unit 8 switches the operation mode based on. For example, the output voltage from the rectifier 2 may be monitored and the operation mode may be switched depending on whether or not the output voltage is within a normal range.

  As described above, in the DC power supply system 1 of the present embodiment, the bidirectional voltage conversion device 6 and the input / output switching unit 7 are configured by adding components to the conventional voltage compensation device, and the bidirectional power conversion. In the circuit 6, both the storage battery charging function and the load voltage compensation function can be realized.

In addition, the addition of the component parts is very small with respect to the cost of the entire system, and the cost increase due to the addition of the function is slight.
This eliminates the need for a charging device that has conventionally been provided independently for charging the storage battery 5, and simplifies, reduces the size, and reduces the cost of the entire system.

  In addition, since an independent charging device is not necessary as described above, another device or the like can be used in the space occupied by the charging device in the conventional DC power supply system. As a result, the capacity of the system can be increased by effectively using the space, and efficient system operation is possible.

  Moreover, the conventional charging device has a configuration that converts an AC input voltage into a DC voltage (AC / DC conversion). However, in this embodiment, the charging voltage is the inductor L1 and the second switch as described above. 12 is generated (DC / DC conversion) by the step-down circuit unit including the second diode D4 and the second diode D4, the configuration for generating the charging voltage is further simplified, and the power conversion efficiency at the time of generation is also simplified. Will also improve. Therefore, high efficiency of the entire system can be realized from the viewpoint of power conversion efficiency and operation rate.

  In this embodiment, the bidirectional power conversion circuit 6 corresponds to the power conversion circuit of the present invention, the control unit 8 corresponds to the control means of the present invention, the OR diode D1 corresponds to the main diode of the present invention, The mode change switch 13 corresponds to the main switch of the present invention.

[Second Embodiment]
Next, the DC power supply system 50 of the second embodiment will be described with reference to FIG. The DC power supply system 50 of the present embodiment shown in FIG. 3 has a plurality of external loads, and each external load has a power supply line, so that the DC voltage from the rectifier 57 is passed through each power supply line. A system that is configured to be supplied in parallel to an external load, and for each external load, a power supply line corresponding to the external load includes a storage battery, a bidirectional power conversion circuit, a mode switch, and a control unit (That is, the configuration excluding the rectifier 2 in the DC power supply system 1 shown in FIG. 1) is connected.

  More specifically, the DC power supply system 50 of the present embodiment includes a first load 51-1, a second load 51-2, a third load 51-3, ..., an Nth load 51-N as external loads. The DC voltage (for example, 380 V) output from the rectifier 57 to the DC bus 61 is input to each external load via a corresponding power supply line. That is, the DC voltage from the rectifier 57 is supplied to the first load 51-1 through the power supply line 61-1, and the DC voltage from the rectifier 57 is supplied to the second load 51-2. The DC voltage from the rectifier 57 is supplied to the third load 51-3 via the power supply line 61-3 and supplied to the third load 51-3. The DC voltage from the rectifier 57 is supplied via the power supply line 61-N.

  In addition, the storage batteries (first storage battery 52-1, second storage battery 52-2, third storage battery 52-3,..., Nth storage battery 52-N) and these storage batteries are charged individually for each external load. Bidirectional power conversion circuit (first bidirectional power conversion circuit 53-1, second bidirectional power conversion circuit 53) having a storage battery charging function and a load voltage compensation function for boosting the voltage of the storage battery and supplying it to the corresponding load -2, the third bidirectional power conversion circuit 53-3, ..., the Nth bidirectional power conversion circuit 53-N, both of which have the same configuration and function as the bidirectional power conversion circuit 6 of the first embodiment. , An input / output switching unit (first input / output switching unit 54-1, second input / output switching unit 54-2, third input / output switching) provided between the bidirectional power conversion circuit and the corresponding power supply line. Unit 54-3,..., N-th input / output switching unit 54-N of the first embodiment. The same configuration and function as the output switching unit 7) and control units (first control unit 55-1, second control unit 55-2, third control unit) that control the operation of each bidirectional power conversion circuit and each input / output switching unit. And N-th control unit 55-N).

  In addition, each control unit can send and receive information to and from each other via the communication line 63, thereby acquiring information on the power consumption of each external load and the capacity of each storage battery, and each system as a whole. Each bidirectional power conversion circuit and input / output switching unit are controlled so that the external load can operate normally.

  In the conventional DC power supply system 100 shown in FIG. 5, each rectifier, each storage battery, and each voltage compensator are configured exclusively for each external load. Therefore, as illustrated in FIG. 5, the first load 101-1 can be operated without any problem because the power consumption is small and the remaining capacity of the corresponding first storage battery 103-1 is large. Although the load 101-2 has a large power consumption, the corresponding second storage battery 103-2 has a large remaining capacity and can be operated without any problem. However, the third load 101-3 has a power consumption (necessary for operation). When the remaining capacity of the corresponding third storage battery 103-3 is small while the capacity of the first storage battery 103-1 is sufficient, the third load 101- 3 could not be operated.

  In contrast, in the DC power supply system 50 of the present embodiment, power is supplied in parallel from the rectifier 2 to a plurality of external loads, and a bidirectional power conversion circuit and the like are provided for each external load. The output voltage from the conversion circuit can be supplied not only to the corresponding external load but also to other external loads other than the corresponding external load.

  In other words, by controlling the operation of each bidirectional power conversion circuit, etc. based on the power consumption of each external load and the information on the charging capacity of each storage battery, the storage battery corresponding to any external load temporarily runs out of capacity. Even if the external load cannot be operated depending on the storage battery, the external load can be operated by receiving power supply from any other storage battery.

  Therefore, as illustrated in FIG. 3 as in FIG. 5, the remaining capacity of the corresponding third storage battery 52-3 is small although the power consumption (power required for operation) of the third load 51-3 is large. In this case, the third load 51-3 can be operated in response to the supply of power from the first storage battery 52-1, which has a relatively large margin.

  In other words, each storage battery provided corresponding to each external load is basically for supplying power to the external load corresponding to itself, but the state of the entire system (capacity of each storage battery and each external load It can be supplied to other external loads in parallel according to the power consumption of the load).

  Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention. Needless to say.

  For example, the configuration of the bidirectional power conversion circuit exemplified in the above embodiment is merely an example, and the specific configuration thereof is not particularly limited as long as it has a function as the above-described bidirectional power conversion circuit.

  In addition, the bidirectional power conversion circuit of the above embodiment has a configuration including a non-insulated power conversion circuit that does not use a transformer, but such a non-insulated type configuration is merely an example, for example, Like a well-known isolated bidirectional power conversion circuit configured to enable bidirectional power conversion by providing a full bridge circuit composed of four semiconductor switches on both the primary side and the secondary side of the transformer, You may comprise with an insulation type circuit.

  DESCRIPTION OF SYMBOLS 1,50,100,120 ... DC power supply system, 2,57 ... Rectifier, 3 ... External load, 4 ... Charger, 5 ... Storage battery, 6 ... Bidirectional power conversion circuit, 7 ... Input / output switching part, 8 ... Control unit, 9, 10 ... power supply line, 10 ... power supply line, 11 ... first switch, 12 ... second switch, 13 ... mode selector switch, 51-1 ... first load, 51-2 ... second load , 51-3 ... 3rd load, 51-N ... Nth load, 52-1 ... 1st storage battery, 52-2 ... 2nd storage battery, 52-3 ... 3rd storage battery, 52-N ... Nth storage battery, 53 -1 ... 1st bidirectional power converter circuit, 53-2 ... 2nd bidirectional power converter circuit, 53-3 ... 3rd bidirectional power converter circuit, 53-N ... Nth bidirectional power converter circuit, 54-1 ... 1st input / output switching part, 54-2 ... 2nd input / output switching part, 54-3 ... 3rd input / output switching part, 54-N ... Nth Output switching unit, 55-1 ... first control unit, 55-2 ... second control unit, 55-3 ... third control unit, 55-N ... Nth control unit, 61 ... DC bus, 61-1 ... power Supply line, 61-2 ... power supply line, 61-3 ... power supply line, 61-N ... power supply line, 63 ... communication line, C1, C11 ... capacitor, D1 ... OR diode, D2 ... bypass diode, D11 ... Diode, D3 ... 1st diode, D4 ... 2nd diode, L1, L11 ... Inductor, L11 ... Inductor

Claims (4)

A rectifier that converts an AC voltage input from the AC power system into a DC voltage and outputs it to a power supply line to an external load;
A storage battery,
A bidirectional power converter provided between the power supply line and the storage battery;
With
The bidirectional power converter is
A storage battery charging function for charging the storage battery by stepping down the DC voltage input from the power supply line and supplying the storage battery to the storage battery, and boosting the voltage of the storage battery to the power supply line A power conversion circuit having a load voltage compensation function for supplying power of the storage battery to the external load by outputting;
A main diode provided on an energization path between the power conversion circuit and the power supply line, allowing energization from the power conversion circuit to the power supply line and preventing energization in the reverse direction;
A main switch connected in parallel with the main diode, and enabling energization from the power supply line to the power conversion circuit by short-circuiting both ends of the main diode;
When the rectifier can normally output the DC voltage , the main switch is closed to short-circuit both ends of the main diode and the power conversion circuit is operated with the storage battery charging function. And a control means for opening the main switch and operating the power conversion circuit with the load voltage compensation function when the voltage cannot be normally output. The DC power supply system according to claim 1 ,
The power conversion circuit has a step-down circuit unit that realizes the storage battery charging function and a step-up circuit unit that realizes the load voltage compensation function,
The booster circuit unit includes at least
An inductor having one end connected to the positive electrode side of the storage battery;
A first switch having one end connected to the negative electrode side of the storage battery and the other end connected to the other end side of the inductor;
A first diode having an anode connected to a connection point between the inductor and the first switch;
Composed of
The step-down circuit unit is at least
A second switch connected in parallel to the first diode, and enabling a current from the cathode side to the anode side of the first diode by short-circuiting both ends of the first diode;
A second diode having an anode connected to one end of the first switch and a cathode connected to the other end of the first switch;
The inductor;
It consists of
When the power conversion circuit is operated by the load voltage compensation function, the control means opens the second switch and controls the opening and closing of the first switch to operate the booster circuit unit to operate the storage battery. When the power conversion circuit is operated with the storage battery charging function, the step-down circuit unit is operated by opening and closing the second switch and controlling the opening and closing of the second switch. A DC power supply system, wherein the DC voltage input from a supply line is stepped down. The DC power supply system according to claim 1 or 2 ,
A configuration in which a plurality of the external loads are provided and each of the external loads has the power supply line so that a DC voltage from the rectifier is supplied in parallel to the external loads via the power supply lines. Has been
The DC power supply system, wherein the bidirectional power converter is connected to the power supply line corresponding to the external load for each external load. A first input / output terminal connected to an external power supply line and a second input / output terminal connected to a storage battery, and a DC voltage input from the power supply line to the first input / output terminal A storage battery charging function for charging the storage battery by stepping down and outputting from the second input / output terminal, and boosting the voltage of the storage battery input from the second input / output terminal to increase the first input / output A power conversion circuit having a power supply function of outputting from the end to the power supply line;
Provided on an energization path between the first input / output end and the power supply line, permitting energization from the first input / output end to the power supply line and preventing energization in the opposite direction. A main diode;
A main switch connected in parallel with the main diode, and enabling energization from the power supply line to the first input / output terminal by short-circuiting both ends of the main diode;
When a predetermined first condition is satisfied, the main switch is closed to short-circuit both ends of the main diode, and the power conversion circuit is operated with the storage battery charging function to determine a predetermined second When the condition is satisfied, the control means for opening the main switch and operating the power conversion circuit with the power supply function,
A bidirectional power conversion device comprising: