JP2015177731A - Power supply device included in power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device that is capable of continuing supplying of a power supply voltage to a control unit without interruption even when electric outage occurs, and has a power conversion efficiency at normal time higher than the conventional one.SOLUTION: A power supply device 1 comprises: a first power supply unit 2 for outputting a first DC voltage; a second power supply unit 3 for outputting a second DC voltage lower than the first DC voltage; and a switching unit 4 for performing switching of the larger one in the first DC voltage and the second DC voltage selected by using rectifying action. The second power supply unit 3: includes an alternative voltage generation unit 6 for generating an alternative voltage higher than a discharge voltage of a storage battery B on the basis of a voltage induced at a secondary winding T21a; and generates the second DC voltage on the basis of the larger one in the alternative voltage and the discharge voltage. When reduction in system voltage causes the first DC voltage to be lower than the second DC voltage, the alternative voltage reduces and becomes lower than the discharge voltage, causing the second power supply unit 3 to start generation of the second DC voltage on the basis of the discharge voltage.

Description

  The present invention relates to a power supply apparatus that supplies a predetermined power supply voltage to a control unit that controls a power storage system in a power storage system that supplies either a system voltage or a discharge voltage of a storage battery to a load.

  2. Description of the Related Art In recent years, the use of power storage systems has been promoted in which a storage battery charged with inexpensive late-night power is discharged in the daytime when power demand is high, thereby leveling the power demand and reducing the electricity bill. FIG. 5 shows a power storage system 20 disclosed in Patent Document 1 as an example of a conventional power storage system. The power storage system 20 mainly has a function of charging the storage battery B by converting the system power from the system G into a direct current and a function of supplying the discharge power of the storage battery B to the load R so as to prevent reverse power flow. The directional power conversion unit 11, the control unit 12 that controls the bidirectional power conversion unit 11, and a power supply device 13 that supplies a power supply voltage to the control unit 12 are provided.

  The power supply device 13 includes an AC / DC converter 14, a DC / DC converter 15, and a switch unit 16. The switch means 16 connects the AC / DC converter 14 and the DC / DC converter 15 at a normal time when no power failure occurs in the system G. At this time, the DC / DC converter 15 supplies a power supply voltage to the control unit 12 based on the power derived from the system power supplied from the AC / DC converter 14. On the other hand, the switch means 16 connects the storage battery B and the DC / DC converter 15 when a power failure occurs in the system G. At this time, the DC / DC converter 15 supplies a power supply voltage to the control unit 12 based on the discharge power of the storage battery B.

  According to the power storage system 20, the bidirectional power converter 11 can be operated by continuously supplying the power supply voltage to the controller 12 even during a power failure.

JP 2012-175801 A

  However, it takes a certain amount of time to detect that a power failure has occurred and to switch the switch means 16. For this reason, in this power storage system 20, unless the output holding time of the AC / DC converter 14 is lengthened by a large-capacitance capacitor provided in the AC / DC converter 14, the switch means 16 is connected to the storage battery B and the DC / DC converter. 15, before the discharge power starts to be supplied to the DC / DC converter 15, the power supply from the AC / DC converter 14 is interrupted, and there is a possibility that a blank period occurs in the power supply voltage supplied to the control unit 12.

  Further, in this power storage system 20, since the AC / DC converter 14 and the DC / DC converter 15 are connected in series at the normal time, loss occurs in both the AC / DC converter 14 and the DC / DC converter 15, and the power There is also a problem that the conversion efficiency decreases.

  The present invention has been made in view of the above circumstances, and the problem is that the power supply voltage can be continuously supplied to the control unit without interruption even when a power failure occurs, and compared with the conventional one. It is another object of the present invention to provide a power supply device having high power conversion efficiency during normal operation.

In order to solve the above problems, a power supply device according to the present invention supplies a predetermined power supply voltage to a control unit that controls the power storage system in a power storage system that supplies either a system voltage or a discharge voltage of a storage battery to a load. A power supply unit,
A first power supply unit that outputs a first DC voltage obtained by rectifying and smoothing a system voltage, a second power supply unit that outputs a second DC voltage set smaller than the first DC voltage, and a first power supply unit A switching element and a primary winding of the transformer that are connected to both of the second power supply unit and switch a larger one of the first DC voltage and the second DC voltage selected by using the rectifying action of the diode. And at least one power supply voltage generator that generates a power supply voltage by converting a voltage induced in the other winding of the transformer by switching into a direct current,
The second power supply unit includes an alternative voltage generation unit that generates an alternative voltage that is higher than the discharge voltage based on a voltage induced in another winding of the transformer. And is configured to generate a second DC voltage based on
When the first DC voltage falls below the second DC voltage due to the drop in the system voltage, and the switching unit starts to switch the second DC voltage generated based on the substitute voltage, the substitute voltage falls and falls below the discharge voltage, The two power supply units start to generate the second DC voltage based on the discharge voltage.

  In this configuration, the switching unit selects the larger one of the first DC voltage and the second DC voltage using the rectifying action of the diode. For this reason, according to this configuration, when a switching target is switched from the first DC voltage to the second DC voltage or from the second DC voltage to the first DC voltage without providing a large-capacity capacitor, a blank period is set. Will not occur. In this configuration, the system voltage is converted into a predetermined power supply voltage to be output to the control unit by one power conversion in the switching unit. For this reason, according to this structure, the power conversion efficiency in normal time can be improved compared with the case where power conversion is performed twice.

  As a configuration of the alternative voltage generation unit in the power supply device, for example, a diode and a capacitor for rectifying and smoothing a voltage induced in another winding, and an alternative voltage obtained by making the voltage after rectifying and smoothing a constant voltage, A configuration including an output series regulator is conceivable.

  Further, when this series regulator has an overcurrent protection function, when the switching unit starts to switch the second DC voltage generated based on the alternative voltage, the fall of the alternative voltage is reduced. It can be realized using.

  According to the present invention, it is possible to continue to supply the power supply voltage to the control unit without interruption even in the event of a power failure, and to provide a power supply device having higher power conversion efficiency at normal time than the conventional one. it can.

It is a block diagram of the electrical storage system provided with the power supply device which concerns on this invention. It is a circuit diagram of the power supply device which concerns on the Example of this invention. It is a wave form diagram which shows the operation | movement at the time of the power failure generation | occurrence | production of the power supply device which concerns on the Example of this invention. It is a circuit diagram of the power supply device which concerns on a comparative example. It is a block diagram of the electrical storage system provided with the conventional power supply device.

  Embodiments of a power supply device according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a power storage system 10 including a power supply device 1 according to an embodiment of the present invention. The power storage system 10 has a function of charging the storage battery B by converting the system power from the system G into a direct current, and a function of supplying the discharge power of the storage battery B to the load R so as not to flow backward by alternating current. Unit 11, control unit 12 that controls bidirectional power conversion unit 11, and power supply device 1 that supplies power supply voltage to control unit 12. The power supply device 1 receives the system voltage of the system G and the discharge voltage of the storage battery B. The control unit 12 includes a first control unit 12a and a second control unit 12b which will be described later.

  As illustrated in FIG. 2, the power supply device 1 according to the embodiment includes a first power supply unit 2 that outputs a first DC voltage obtained by converting a system voltage from the system G into a DC, and a second power source that outputs a second DC voltage. A second power supply unit 3, a switching unit 4 connected to both the first power supply unit 2 and the second power supply unit 3 for switching the larger one of the first DC voltage and the second DC voltage, and the first control unit 12a The first power supply voltage generation unit 5a for supplying the power supply voltage to the second control unit 12b, and the second power supply voltage generation unit 5b for supplying the power supply voltage to the second control unit 12b.

  The first power supply unit 2 includes a rectifier diode D4 and a smoothing capacitor C1. The first power supply unit 2 rectifies and smoothes the system voltage thereby to generate the first DC voltage. When the system voltage is AC 200 [V], the first DC voltage is 200 [V] × √2≈283 [V]. However, the system voltage may fluctuate within a range of ± 20%. For this reason, the first DC voltage may also vary within the range of 160 [V] × √2≈226 [V] and 240 [V] × √2≈339 [V].

  The second power supply unit 3 includes a diode D1, a diode D2, a first transformer T1, a first switching element Q1, a rectifier diode D3, and a smoothing capacitor C1. The smoothing capacitor C1 is also a component of the first power supply unit 2.

  When the discharge voltage of the storage battery B is higher than an alternative voltage described later, the discharge voltage input through the diode D1 is applied to the series circuit including the primary winding T11 of the first transformer T1 and the first switching element Q1. On the other hand, when the discharge voltage of the storage battery B is smaller than the alternative voltage, the alternative voltage input through the diode D2 is applied to the series circuit.

  When the first switching element Q1 repeats ON / OFF, the discharge voltage or the alternative voltage is switched, and an AC voltage is induced in the secondary winding T12 of the first transformer T1. Then, the second power supply unit 3 rectifies and smoothes the AC voltage by the rectifier diode D3 and the smoothing capacitor C1, and generates a second DC voltage smaller than the first DC voltage. When the system voltage is AC 200 [V], for example, the second DC voltage is set to 180 [V] smaller than 226 [V] which is the lower limit value of the first DC voltage.

  In a normal time when no power failure occurs in the system G, the larger one of the first DC voltage and the second DC voltage, that is, the first DC voltage appears at both ends of the smoothing capacitor C1. At this time, it can be said that the second power supply unit 3 operates with no load. On the other hand, when a power failure occurs in the system G, the magnitude relationship between the first DC voltage and the second DC voltage is reversed, and the second DC voltage appears at both ends of the smoothing capacitor C1.

  The switching unit 4 includes a series circuit including a primary winding T21 of the second transformer T2 and a second switching element Q2. When the second switching element Q2 repeats ON / OFF, the first DC voltage or the second DC voltage appearing at both ends of the smoothing capacitor C1 is switched, and the other winding of the second transformer T2, that is, the primary winding T21a. , T21b and the secondary winding T22 are induced with an alternating voltage.

  The second power supply unit 3 further includes a primary winding T21a, a rectifier diode D5, a smoothing capacitor C2, and a series regulator 6 (corresponding to the “alternative voltage generation unit” of the present invention). The rectifier diode D5 and the smoothing capacitor C2 rectify and smooth the AC voltage induced in the primary winding T21a by the switching of the second switching element Q2. And the series regulator 6 produces | generates an alternative voltage larger than the discharge voltage of the storage battery B based on the voltage after this rectification | straightening smoothing. When the discharge voltage when the storage battery B is fully charged is 190 [V], the alternative voltage is set to 200 [V], for example.

  The series regulator 6 has an overcurrent protection function. The overcurrent protection function works when the output current of the series regulator 6 that flows to the primary winding T11 of the transformer T1 via the diode D2 exceeds a predetermined threshold value. When the overcurrent protection function is activated, the series regulator 6 reduces the alternative voltage.

  The first power supply voltage generator 5a includes a primary winding T21b, a rectifier diode D6, and a smoothing capacitor C3. The rectifier diode D6 and the smoothing capacitor C3 rectify and smooth the AC voltage induced in the primary winding T21b by the switching of the second switching element Q2. The direct current voltage thus obtained is supplied as a power supply voltage to the first controller 12a.

  Similarly, the second power supply voltage generation unit 5b includes a secondary winding T22, a rectifier diode D7, and a smoothing capacitor C4. The rectifier diode D7 and the smoothing capacitor C4 rectify and smooth the AC voltage induced in the secondary winding T22 by the switching of the second switching element Q2. The direct current voltage thus obtained is supplied as a power supply voltage to the second controller 12b.

  Next, an example of the operation of the power supply device 1 will be described with reference to FIG. In this example, in normal times, the system voltage is AC 200 [V], the alternative voltage (DC) is 200 [V], the discharge voltage (DC) is 190 [V], and the second DC voltage is 180 [V]. is there.

  At the normal time from time t0 to t1, as shown in FIG. 3D, the series regulator 6 outputs an alternative voltage of 200 [V], while as shown in FIG. A discharge voltage of [V] is output. For this reason, the input voltage of the second power supply unit 3 (the voltage applied to the series circuit composed of the primary winding T11 and the first switching element Q1) is, as shown in FIG. ] And the second power supply unit 3 outputs a second DC voltage of 180 [V] based on the alternative voltage.

  Moreover, in the normal time of time t0-t1, the 1st power supply part 2 outputs the 1st DC voltage of 283 [V]. Then, the larger of the first DC voltage and the second DC voltage, that is, the first DC voltage of 283 [V] appears at both ends of the smoothing capacitor C1, as shown in FIG. The first DC voltage is pulsating because it includes commercial ripple.

  When a power failure occurs at time t1, the first DC voltage gradually decreases as shown in FIG. When the first DC voltage falls below the second DC voltage at time t2, the rectifier diode D4 is turned OFF and the rectifier diode D3 is turned ON at the same time, and 180 outputted from the second power supply unit 3 to both ends of the smoothing capacitor C1. The second DC voltage of [V] appears, and the switching unit 4 starts to switch the second DC voltage. As a result, the input power of the second power supply unit 3 (power input to the series circuit composed of the primary winding T11 and the first switching element Q1) is 1. Increase from 5 [W].

  When the input power of the second power supply unit 3, that is, the output current of the series regulator 6 increases, the overcurrent protection function of the series regulator 6 works, and the alternative voltage starts to decrease as shown in FIG. When the alternative voltage falls below the discharge voltage of 190 [V] at time t3, the diode D2 is turned off at the same time as the diode D2 is turned on. As shown in FIG. A second DC voltage is generated based on the voltage.

  Next, the superiority of the power supply device 1 according to the embodiment over the power supply device 1 ′ according to the comparative example will be described with reference to FIG. 4.

  As shown in FIG. 4, the power supply device 1 ′ is different from the power supply device 1 in that the second power supply unit 3 ′ is configured to always generate the second DC voltage based on the discharge voltage of the storage battery B. Yes. For this reason, in this power supply device 1 ′, the electric power stored in the storage battery B continues to be consumed little by little even in a normal time when no power failure occurs (1.5 [W] in the above embodiment). If the battery is not properly charged, the storage battery B may be overdischarged. On the other hand, in the power supply device 1 according to the embodiment, since the alternative voltage is used in normal times and the discharge voltage of the storage battery B is used only during a power failure, the power of the storage battery B continues to be consumed in the normal state. It will never be.

  Thus, according to the power supply device 1 according to the embodiment of the present invention, the switching unit 4 selects the larger one of the first DC voltage and the second DC voltage using the rectifying action of the diodes D3 and D4. Therefore, when the object to be switched is switched from the first DC voltage to the second DC voltage or from the second DC voltage to the first DC voltage, a blank period does not occur. Further, according to the power supply device 1, the system voltage is converted into a predetermined power supply voltage to be output to each of the control units 12a and 12b by one power conversion in the switching unit 4, so that the power conversion is performed twice. Thus, the power conversion efficiency during normal operation can be improved. Furthermore, according to the power supply device 1, since an alternative voltage is used instead of the discharge voltage of the storage battery B at the normal time, the storage battery B can be prevented from being overdischarged.

  As mentioned above, although the Example of the power supply device which concerns on this invention has been described, the structure of this invention is not limited to this Example.

  For example, the power supply device 1 according to the embodiment includes two power supply voltage generation units (a first power supply voltage generation unit 5a and a second power supply voltage generation unit 5b), but the number of power supply voltage generation units should be controlled. You may increase / decrease suitably according to the number of control parts.

  Moreover, in the power supply device 1 according to the embodiment, the series regulator 6 is used as the alternative voltage generation unit. However, an alternative voltage larger than the discharge voltage of the storage battery B can be output at the normal time, and the output current becomes excessive. A substitute voltage generator that can lower the substitute voltage at this time may be used.

DESCRIPTION OF SYMBOLS 1 Power supply device 2 1st power supply part 3 2nd power supply part 4 Switching part 5a 1st power supply voltage generation part 5b 2nd power supply voltage generation part 6 Series regulator (alternative voltage generation part)
DESCRIPTION OF SYMBOLS 10 Power storage system 11 Bidirectional power conversion part 12 Control part 12a 1st control part 12b 2nd control part B Storage battery G System | strain C1, C2, C3, C4 Smoothing capacitor D1, D2 Diode D3, D4, D5, D6, D7 Rectifier diode Q1 first switching element Q2 second switching element T1 first transformer T2 second transformer

Claims (3)

In a power storage system that supplies either a system voltage or a discharge voltage of a storage battery to a load, a power supply device that supplies a predetermined power supply voltage to a control unit that controls the power storage system,
A first power supply unit that outputs a first DC voltage obtained by rectifying and smoothing the system voltage;
A second power supply unit that outputs a second DC voltage set smaller than the first DC voltage;
A switching element that is connected to both the first power supply unit and the second power supply unit and switches a larger one of the first DC voltage and the second DC voltage selected by using a rectifying action of a diode; A switching unit consisting of the primary winding of the transformer;
At least one power supply voltage generating unit that converts the voltage induced in the other windings of the transformer by the switching into a direct current to generate the power supply voltage;
With
The second power supply unit includes an alternative voltage generation unit that generates an alternative voltage that is higher than the discharge voltage based on a voltage induced in another winding of the transformer. Configured to generate the second DC voltage based on the larger one of them,
When the first DC voltage falls below the second DC voltage due to a decrease in the system voltage, and the switching unit starts switching the second DC voltage generated based on the alternative voltage, the alternative voltage decreases. And the second power supply unit starts generating the second DC voltage based on the discharge voltage. The alternative voltage generator is
A diode and a capacitor for rectifying and smoothing a voltage induced in the other winding;
A series regulator that outputs the alternative voltage obtained by making the rectified and smoothed voltage constant;
The power supply device according to claim 1, comprising: The series regulator has an overcurrent protection function,
The overcurrent protection function is activated when the switching unit starts to switch the second DC voltage generated based on the alternative voltage, and as a result, the alternative voltage decreases. The power supply described.

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