JP6704838B2 - Power supply device provided in the power storage system - Google Patents

Description

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

In recent years, a storage battery that has been charged with inexpensive late-night power is discharged in the daytime when power demand is high, so that a power storage system that equalizes power demand and reduces electricity charges is being used. FIG. 4 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 converting the system power from the system G into a DC power to charge the storage battery B, and a function of converting the discharge power of the storage battery B into an AC power and supplying it to the load R so as not to flow backward. The power conversion unit 11, the control unit 12 that controls the bidirectional power conversion unit 11, and the power supply device 13 that supplies a predetermined 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 means 16. The switch means 16 connects the AC/DC converter 14 and the DC/DC converter 15 during a normal time when a power failure does not occur in the system G. At this time, the DC/DC converter 15 supplies a predetermined 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 at the time of a power failure in which the system G has a power failure. At this time, the DC/DC converter 15 supplies a predetermined power supply voltage to the control unit 12 based on the discharge power of the storage battery B.

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

JP2012-175801A

However, it takes some time to detect the occurrence of a power failure and switch the switch means 16. For this reason, in this electricity storage system 20, unless the output holding time of the AC/DC converter 14 is kept long by the large-capacity capacitor (not shown) provided in the AC/DC converter 14, the switch means 16 is connected to the storage battery B. Before the discharge power is supplied to the DC/DC converter 15 by connecting to the DC/DC converter 15, the power supply from the AC/DC converter 14 is interrupted, and a blank period may occur in the power supply voltage supplied to the control unit 12. There is.

In addition, in the electricity storage system 20, the AC/DC converter 14 and the DC/DC converter 15 are connected in series at normal times, so that loss occurs in both the AC/DC converter 14 and the DC/DC converter 15, and the power consumption is reduced. There is also a problem that the conversion efficiency is lowered.

The present invention has been made in view of the above circumstances, and its object is to be able to continuously supply the power supply voltage to the control unit without interruption even during a power failure, and moreover, as compared with the conventional one. It is to provide a power supply device having high power conversion efficiency in normal times.

In order to solve the above problems, a power supply device according to the present invention is a power supply system that supplies a predetermined power supply voltage to a control unit that controls the power storage system in a power storage system that supplies a system voltage or a discharge voltage of a storage battery to a load. 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 lower than the first DC voltage, and a first power supply. Connected to both the power supply section and the second power supply section, and switching a larger one of the first DC voltage and the second DC voltage selected by the rectifying action of the diode, the switching section including a switching element and a primary winding of the transformer. And at least one power supply voltage generation unit that generates a predetermined power supply voltage by converting the voltage induced in the other winding of the transformer by the switching into a direct current, and the second power supply unit rectifies and smoothes the system voltage. The step-up chopper circuit that generates the second DC voltage from the larger one of the third DC voltage and the discharge voltage obtained by (1) If the system voltage is within the normal range, the second power supply unit Generates the second DC voltage from the third DC voltage, the switching unit switches the first DC voltage, and (2) when the system voltage is below the lower limit of the normal range, the second power supply unit discharges the discharge voltage. The second direct current voltage is generated by the switching unit and the switching unit switches the second direct current voltage.

In this configuration, the switching unit switches the larger one of the first DC voltage and the second DC voltage selected by the rectifying action of the diode. Therefore, according to this configuration, when the switching target of the switching unit 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, There is no blank period. Further, in this configuration, during normal operation when the system voltage is within the normal range, 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. Therefore, according to this configuration, the power conversion efficiency in the normal time can be improved as compared with the case where the power conversion is performed twice.

The step-up chopper circuit of the power supply device includes a voltage detector that detects an input voltage. When the voltage detected by the voltage detector is below a preset threshold value, the step-up chopper operation changes the second DC voltage. It is preferable that the second DC voltage is generated by generating the voltage, and otherwise generating the second DC voltage by passing the input voltage, not by the step-up chopper operation.

In this configuration, the boost chopper operation is performed in the boost chopper circuit when the voltage input to the boost chopper circuit falls below the preset threshold value. Conversely, if the voltage input to the boost chopper circuit is equal to or higher than the threshold value, the boost chopper operation is not performed. Therefore, according to this configuration, the loss due to the boost chopper operation can be reduced.

In the power supply device, the upper limit of the discharge voltage is smaller than the lower limit of the third DC voltage when the system voltage is within the normal range, and the threshold value is set between the upper limit and the lower limit of the discharge voltage. Is preferred.

With this configuration, it is possible to prevent power consumption of the storage battery during normal operation when the system voltage is within the normal range. Further, according to this configuration, even after the voltage input to the boost chopper circuit is switched from the third DC voltage to the discharge voltage of the storage battery due to a significant decrease in the system voltage, the discharge of the storage battery progresses and the discharge of the storage battery proceeds. Since the boost chopper operation is not performed until the voltage falls below the threshold value, the loss due to the boost chopper operation can be reduced.

The power supply device uses a diode bridge to rectify the system voltage to obtain the first DC voltage, and uses some diodes that form the diode bridge to rectify the system voltage to obtain the third DC voltage. It is preferable that it is configured to be performed as follows.

In this structure, part of the diode bridge used for rectification to obtain the first DC voltage is diverted to perform rectification to obtain the third DC voltage. Therefore, according to this structure, the number of components for obtaining the third DC voltage can be reduced.

According to the present invention, it is possible to provide a power supply device capable of continuously supplying a power supply voltage to a control unit without interruption even during a power failure, and having a higher power conversion efficiency in a normal time than a conventional device. ..

1 is a block diagram of a power storage system including a power supply device according to the present invention. It is a circuit diagram 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 the modification of this invention. 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 1A according to an embodiment of the present invention. The power storage system 10 has a function of converting the system power from the system G into a DC power to charge the storage battery B, and a function of converting the discharge power of the storage battery B into an AC power and supplying the AC power to the load R so as not to flow backward. The control unit 12 includes a unit 11, a control unit 12 that controls the bidirectional power conversion unit 11, and a power supply device 1A that supplies a predetermined power supply voltage to the control unit 12. The system voltage of the system G and the discharge voltage of the storage battery B are input to the power supply device 1A. The control unit 12 is composed of a first control unit 12a and a second control unit 12b described later.

As shown in FIG. 2, the power supply device 1A according to the present embodiment includes a first power supply unit 2 that outputs a first DC voltage obtained by converting the system voltage of the system G into a DC voltage, and a second DC unit that outputs a second DC voltage. A second power supply unit 3, a switching unit 6 connected to both the first power supply unit 2 and the second power supply unit 3 and switching the larger one of the first DC voltage and the second DC voltage, and the first control unit 12a. And a second power supply voltage generation unit 7b that supplies a predetermined power supply voltage to the second control unit 12b.

Further, the power supply device 1A includes two rectifier diodes D1 and D2 whose cathodes are connected to each other, a backflow prevention diode D3 which is connected to the storage battery B, and a smoothing capacitor C2 which is connected in parallel to the input of the second power supply unit 3. Is equipped with. The cathodes of the rectifier diodes D1 and D2 are connected to the cathode of the backflow prevention diode D3.

The first power supply unit 2 includes a diode bridge DB1 and a smoothing capacitor C1. The first power supply unit 2 rectifies and smoothes the system voltage by these to generate a 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%. Therefore, the first DC voltage may also fluctuate within the range of 160 [V]×√2≈226 [V] to 240 [V]×√2≈339 [V].

The rectifying diodes D1 and D2, the smoothing capacitor C2, and the two diodes connected to the low-potential-side DC line of the four diodes forming the diode bridge DB1 rectify and smooth the system voltage to generate a third DC voltage. To generate. That is, a total of four diodes, two of the rectifying diodes D1 and D2 and two diodes connected to the low potential side DC line of the four diodes forming the diode bridge DB1, form a bridge rectifying diode. The bridge rectifier diode and the smoothing capacitor C2 convert the system voltage to DC, and the DC-converted voltage appears as a third DC voltage across the smoothing capacitor C2. Like the first DC voltage, the third DC voltage may fluctuate within the range of 226 [V] to 339 [V].

The second power supply unit 3 includes a booster chopper circuit including a coil L, a rectifying diode D4, a first switching element Q1, a smoothing capacitor C1 and a switching control unit 5, and a voltage detection unit 4. The smoothing capacitor C1 is also a component of the first power supply unit 2.

When the third DC voltage is higher than the discharge voltage of the storage battery B, the third DC voltage appearing across the smoothing capacitor C2 becomes the input voltage of the boost chopper circuit. On the other hand, when the discharge voltage of the storage battery B is higher than the third DC voltage, the discharge voltage of the storage battery B appearing across the smoothing capacitor C2 becomes the input voltage of the boost chopper circuit. The voltage input to the boost chopper circuit is automatically switched without a blank period by the rectifying action of the rectifying diodes D1 and D2, the backflow prevention diode D3 and the diode bridge DB1.

In this embodiment, the discharge voltage of the storage battery B fluctuates within the range of 144 [V] to 196.8 [V] (when fully charged). As described above, since the lower limit of the third DC voltage in the normal state is 226 [V], the third DC voltage is normally input to the boost chopper circuit. Conversely, the discharge voltage of the storage battery B is input to the step-up chopper circuit only when the system voltage, and thus the third DC voltage, is significantly reduced due to the power failure.

When the switching controller 5 continuously switches the first switching element Q1, the boost chopper circuit boosts the input voltage. On the other hand, when the switching control unit 5 does not switch the first switching element Q1, the boost chopper circuit allows the input voltage to pass as it is. By these operations, the second power supply unit 3 generates the second DC voltage.

The voltage detection unit 4 of the second power supply unit 3 determines the magnitude relationship between the voltage input to the boost chopper circuit and the preset threshold Vt, and transmits the result to the switching control unit 5. When the voltage input to the boost chopper circuit is equal to or higher than the threshold value Vt, the switching control unit 5 does not switch the first switching element Q1 (maintains the off state). In this case, the second power supply unit 3 outputs the input voltage as it is as the second DC voltage. However, since a voltage drop occurs in the coil L and the rectifying diode D4, the second DC voltage is slightly lower than the third DC voltage (=first DC voltage). On the other hand, when the voltage input to the boost chopper circuit is less than the threshold value Vt, the switching control unit 5 switches the switching element Q1 to boost the input voltage to the threshold value Vt. In this case, the second power supply unit 3 outputs the voltage after being boosted to the threshold value Vt as the second DC voltage.

In this embodiment, the threshold value Vt is set to 168 [V]. That is, the threshold value Vt is set between the lower limit (144 [V]) and the upper limit (196.8 [V]) of the discharge voltage of the storage battery B. Even if the input voltage of the boost chopper circuit is switched from the third DC voltage to the discharge voltage of the storage battery B due to a power failure, the boost chopper operation is not performed until the discharge voltage of the storage battery B falls below the threshold value Vt. There is no loss due to chopper operation.

The larger of the first DC voltage and the second DC voltage selected by the rectifying action of the rectifying diode D4 and the diode bridge DB1 appears across the smoothing capacitor C1. When the first DC voltage is higher than the second DC voltage, that is, when the first DC voltage appears across the smoothing capacitor C1, it can be said that the second power supply unit 3 operates without a load.

The switching unit 6 includes a series circuit of the primary winding T1 of the transformer T and the second switching element Q2. When a switching control circuit (not shown) continuously switches the second switching element Q2, the first DC voltage or the second DC voltage appearing across the smoothing capacitor C1 is switched, and the other winding of the transformer T, that is, , An AC voltage is induced in the secondary winding T2 and the other primary winding T3.

The first power supply voltage generator 7a includes a primary winding T3, a rectifying diode D5, and a smoothing capacitor C3. The rectifier diode D5 and the smoothing capacitor C3 rectify and smooth the AC voltage induced in the primary winding T3 by the switching of the second switching element Q2. Then, the DC voltage thus obtained is supplied to the first controller 12a as a power supply voltage.

Similarly, the second power supply voltage generator 7b includes a secondary winding T2, a rectifying diode D6, and a smoothing capacitor C4. The rectifying diode D6 and the smoothing capacitor C4 rectify and smooth the AC voltage induced in the secondary winding T2 by the switching of the second switching element Q2. Then, the DC voltage thus obtained is supplied to the second controller 12b as a power supply voltage.

The operation of the power supply device 1A according to this embodiment will be described in more detail.

[Condition 1] System G: Normal Under this condition, since the lower limit of the third DC voltage (226 [V]) is larger than the upper limit of the discharge voltage of the storage battery B (196.8 [V]), the discharge voltage of the storage battery B is The third DC voltage becomes the input voltage of the second power supply unit 3, regardless of Further, under this condition, the input voltage of the second power supply unit 3 is larger than the threshold value Vt (168 [V]), so the second power supply unit 3 outputs the third DC voltage as it is as the second DC voltage (however, The second DC voltage is slightly smaller than the third DC voltage by the voltage drop in the coil L and the rectifying diode D4). Therefore, the first DC voltage slightly larger than the third DC voltage appears across the smoothing capacitor C1. Then, the second power supply unit 3 operates with no load.

[Condition 2] System G: power failure, 168 [V]≦discharge voltage of storage battery B≦196.8 [V]
Under this condition, since the third DC voltage is zero, the discharge voltage of the storage battery B becomes the input voltage of the second power supply unit 3. Further, under this condition, the input voltage of the second power supply unit 3 is equal to or higher than the threshold value Vt (168 [V]), so the second power supply unit 3 outputs the discharge voltage of the storage battery B as the second DC voltage as it is (however, the coil A voltage drop occurs at L and the rectifying diode D4). Further, under this condition, the first DC voltage is also zero. Therefore, the second DC voltage appears across the smoothing capacitor C1. As a result, the second power supply unit 3 operates with a load, and the discharge voltage of the storage battery B decreases.

[Condition 3] System G: Power failure, 144 [V]≦discharge voltage of storage battery B<168 [V]
Under this condition, since the third DC voltage is zero, the discharge voltage of the storage battery B becomes the input voltage of the second power supply unit 3. Further, under this condition, since the input voltage of the second power supply unit 3 is smaller than the threshold value Vt (168 [V]), the second power supply unit 3 boosts the discharge voltage of the storage battery B to the threshold value Vt by the boost chopper operation, The boosted voltage is output as the second DC voltage. Further, under this condition, the first DC voltage is also zero. Therefore, the second DC voltage appears across the smoothing capacitor C1. As a result, the second power supply unit 3 operates with a load, and the discharge voltage of the storage battery B decreases.

When a power failure occurs when the condition 1 is satisfied (normal time), the condition 2 or the condition 3 is satisfied depending on the amount of the discharge voltage of the storage battery B. If the condition 2 is satisfied for a long time, the discharge voltage of the storage battery B falls below the threshold value Vt, and the condition 3 is satisfied. When the power failure is restored when the condition 2 or the condition 3 is satisfied (at the time of power failure), the condition 1 is satisfied.

It should be noted that the reason why the discharge voltage of the storage battery B is boosted when the condition 3 is satisfied is that when the voltage supplied to the switching unit 6 becomes small, the current flowing through the transformer T and the second switching element Q2 increases, and This is because the loss in the switching unit 6 increases accordingly.

As described above, according to the power supply device 1A of the embodiment of the present invention, the larger one of the first DC voltage and the second DC voltage is selected by the rectifying action of the diode D4 and the diode bridge DB1. No blank period occurs when the switching target of 6 switches from the first DC voltage to the second DC voltage or from the second DC voltage to the first DC voltage. Further, according to this power supply device 1A, at a normal time when the system voltage is within the normal range, the system voltage is output to each of the control units 12a and 12b by one power conversion in the switching unit 6, and the predetermined power supply voltage is output. As a result, the power conversion efficiency under normal conditions can be improved as compared with the case where the power conversion is performed twice.

Although the embodiment of the power supply device according to the present invention has been described above, the configuration of the present invention is not limited to this embodiment.

For example, the power supply device 1A according to the embodiment includes two power supply voltage generation units (first power supply voltage generation unit 7a and second power supply voltage generation 7b), but the number of power supply voltage generation units should be controlled. You may increase or decrease according to the number of copies.

Further, in the power supply device 1A according to the embodiment, the system voltage is rectified by using the rectifier diodes D1 and D2 and a part of the diode bridge DB1, but as in the power supply device 1B shown in FIG. A diode bridge DB2 may be provided instead of D2, and the system voltage may be rectified only by the diode bridge DB2. However, in this case, the number of parts increases.

Further, the upper and lower limits of the discharge voltage of the storage battery B and the threshold value Vt in the power supply device 1A according to the embodiment are merely examples and can be changed. However, it is preferable that the upper limit of the discharge voltage is smaller than the lower limit (226 [V]) of the normal third DC voltage, and the threshold Vt is between the upper limit and the lower limit of the discharge voltage of the storage battery B.

1 Power Supply Device 2 First Power Supply Section 3 Second Power Supply Section 4 Voltage Detection Section 5 Switching Control Section 6 Switching Section 7a First Power Supply Voltage Generation Section 7b Second Power Supply Voltage Generation Section 10 Storage System 11 Bidirectional Power Conversion Section 12 Control Section 12a 1st control part 12b 2nd control part B Storage battery G System C1, C2, C3, C4 Smoothing capacitor D1, D2, D4, D5, D6 Rectifying diode D3 Backflow prevention diode DB1, DB2 Diode bridge L Coil Q1 1st switching element Q2 Second switching element T Transformer

Claims (4)

In a power storage system that supplies 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 lower than the first DC voltage;
A switching element and a transformer that are connected to both the first power supply unit and the second power supply unit and switch the larger one of the first DC voltage and the second DC voltage selected by the rectifying action of a diode. A switching unit consisting of a primary winding,
At least one power supply voltage generation unit that converts the voltage induced in the other winding of the transformer by the switching to generate the predetermined power supply voltage;
Equipped with
The second power supply unit includes a step-up chopper circuit that generates the second DC voltage from the larger one of the third DC voltage and the discharge voltage obtained by rectifying and smoothing the system voltage.
(1) When the system voltage is within a normal range, the second power supply unit generates the second DC voltage from the third DC voltage, and the switching unit switches the first DC voltage. (2) When the system voltage is below the lower limit of the normal range, the second power supply unit generates the second DC voltage from the discharge voltage, and the switching unit causes the second DC voltage. A power supply device which is characterized in that it switches. The boost chopper circuit includes a voltage detector that detects an input voltage. When the voltage detected by the voltage detector falls below a preset threshold, the boost chopper operation generates the second DC voltage. However, in other cases, the power supply device according to claim 1, wherein the second DC voltage is generated not by the boost chopper operation but by passing the input voltage. The upper limit of the discharge voltage is smaller than the lower limit of the third DC voltage when the system voltage is within the normal range, and the threshold value is set between the upper limit and the lower limit of the discharge voltage. ,
The power supply device according to claim 2, wherein: Rectification of the system voltage to obtain the first DC voltage is performed by a diode bridge,
Rectification of the system voltage to obtain the third DC voltage is performed by using some of the diodes forming the diode bridge,
The power supply device according to any one of claims 1 to 3, wherein:

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