JP5941826B2 - Bidirectional power supply device for secondary battery and control method thereof - Google Patents

Description

The present invention relates to a bi-directional power supply device for a secondary battery that rapidly switches from charging (powering) to discharging (regeneration) or rapidly from discharging to charging when charging and discharging the secondary battery, and control thereof. Regarding the method.

In Patent Document 1, a bidirectional AC-DC converter in which an AC side terminal is connected to an AC power source, a DC side terminal is connected to a DC bus, one end is connected to the DC bus, and the other end is connected to a battery (sample). A charging / discharging test system including a connected bidirectional DC-DC converter and a charging / discharging device having a control device that controls the bidirectional DC-DC converter to control charging / discharging of the battery by the bidirectional DC-DC converter. Proposed.

Furthermore, in a charge / discharge circuit of a secondary battery that combines a bidirectional high-frequency isolated converter and a bidirectional chopper circuit, sudden switching from charging (powering) to discharging (regeneration) or from discharging to charging is also performed. Yes.

JP 2012-154793 A

However, in the conventional charge / discharge circuit, when switching from charge (power running) to discharge (regeneration) or from discharge to charge, a stop time is required to switch the input and output switching elements of the bidirectional converter. In order to compensate for this stop time, a capacitor with a large capacity and high withstand voltage is required, and since there is no electrolytic capacitor with high withstand voltage, an electrolytic capacitor is connected in series. Since the total capacity is halved when connected to the cable, there is a problem that it becomes expensive and bulky.

The present invention has been made in view of such circumstances, and there is no power supply stop time at the time of switching from charging to discharging or switching from discharging to charging, and therefore a bidirectional battery for a secondary battery that does not require a large capacity capacitor. An object of the present invention is to provide a power supply device and a control method thereof.

A bi-directional power supply device for a secondary battery according to the first invention that meets the above-mentioned object is provided with a plurality of converters comprising bi-directional high-frequency isolated converters or bridge converters that require a stop period in switching, and connected to the converter In the bidirectional power supply device for a secondary battery that includes a bidirectional chopper that performs switching between charging and discharging of the secondary battery,
Converter A and converter B obtained by dividing the converter into two parts;
A capacitor provided between the converter and the bidirectional chopper;
At the time of switching between charge and discharge, 1) process 2 for stopping the converter B while maintaining the forward operation of the converter A 1, 2) process 2 for stopping the converter A and causing the converter B to perform reverse operation; 3) Control means for sequentially performing the process 3 for reversely operating the converter A. Here, the forward operation refers to an operation for performing any one of “charging or discharging” of the secondary battery, and the reverse operation refers to performing any one of the operations for “charging or discharging” described above ( same as below).

A bidirectional power supply for a secondary battery according to a second aspect of the invention is connected to a plurality of converters composed of bidirectional high-frequency isolated converters or bridge converters that require switching and a stop period. In the bidirectional power supply device for the secondary battery that includes a bidirectional chopper and switches between charging and discharging of the secondary battery,
A converter C that is one of the converters and is normally stopped;
A converter D other than the converter C;
Control means for stopping the converter D and reversely operating the converter C when the secondary battery connected to the converter D is switched from the forward operation to the reverse operation.
When converter C operates and converter D stops, converter C replaces converter D and converter D stops (the same applies to the fourth invention).

According to a third aspect of the present invention, there is provided a control method for a bi-directional power supply device for a secondary battery, wherein a plurality of converters including a bi-directional high-frequency isolated converter or a bridge converter that require switching and a switching period are connected to the converter. In the control method of the bidirectional power supply device for a secondary battery that has a bidirectional chopper that switches between charging and discharging of the secondary battery,
A capacitor is provided between the converter and the bidirectional chopper, and the converter is divided into a converter A and a converter B,
Further, when switching between charging and discharging, 1) the first step in which the converter A stops the converter B while maintaining the state, and 2) the converter A is stopped and the converter B is operated in reverse. A second step, and 3) a third step of reversely operating the converter A.

According to a fourth aspect of the present invention, there is provided a control method for a bi-directional power supply device for a secondary battery, wherein a plurality of converters including a bi-directional high-frequency isolated converter or a bridge converter that require switching and a switching period are connected to the converter. In the control method of the bidirectional power supply device for the secondary battery that switches between charging and discharging of the secondary battery,
One of the converters is a converter C that is always stopped,
When the secondary battery connected to the converter D other than the converter C is switched from the forward operation to the reverse operation, the converter D is stopped and the converter C is reversely operated.

In the control method for the secondary battery bidirectional power supply device according to the first invention and the secondary battery bidirectional power supply device according to the third invention, the plurality of converters are divided into the converter A and the converter B, and When switching from charging to discharging or switching from discharging to charging of the secondary battery, 1) stop converter B and operate converter A as it is, 2) take a stop period of converter B, and reversely operate converter B. After the converter A is stopped, 3) the converter A is stopped, and then the converter A is operated reversely to switch the converters A and B. Therefore, even if the converter has a stop period, the secondary battery is always used. Is connected to the power supply side, and no abnormal high voltage is generated in the DC bus formed between the converter and the bidirectional chopper. Therefore, a capacitor having a high withstand voltage and a large capacity is not required, and the equipment is small and inexpensive.

In the control method for the secondary battery bidirectional power supply device according to the second invention and the secondary battery bidirectional power supply device according to the fourth invention, a converter C that is normally stopped is provided, and the converter D is charged and discharged. When switching is performed, the converter C is operated during the stop period of the converter D, so that no abnormal high voltage is generated in the DC bus formed between the converter and the bidirectional chopper. This eliminates the need for a capacitor with a high withstand voltage and a large capacity, and makes the equipment small and inexpensive.

1 is a block diagram of a bidirectional power supply device for a secondary battery according to an embodiment of the present invention. It is operation | movement explanatory drawing of the bidirectional | two-way AC / DC inverter and bidirectional chopper used for the bidirectional | two-way power supply device for secondary batteries. It is operation | movement explanatory drawing of the bidirectional | two-way high frequency insulation type converter used for the bidirectional | two-way power supply device for secondary batteries. It is explanatory drawing of the control method (charge to discharge) of the bidirectional power supply device for secondary batteries. It is a graph which shows the change of DC bus voltage. It is explanatory drawing of the control method (discharge to charge) of the bidirectional power supply device for secondary batteries. It is a graph which shows the change of DC bus voltage. It is a block diagram of the bidirectional power supply device for a secondary battery according to another embodiment of the present invention.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, a bidirectional power supply device 10 for a secondary battery according to an embodiment of the present invention includes a bidirectional AC / DC inverter 12 connected to a power supply 11 and the bidirectional AC / DC inverter 12. Bidirectional high-frequency isolated converters 13 and 13a (an example of converters A and B in which a plurality of converters are divided into two) connected to a DC bus between the bidirectional high-frequency isolated converters 13 and 13a and the secondary battery 14 15, a bidirectional DC / DC chopper (an example of a bidirectional chopper) 16 connected via 15, a capacitor 17 connected to the DC bus 15, and a control device 18. These will be described in detail below. The bidirectional high-frequency isolated converter 13 corresponds to the converter A, and the bidirectional high-frequency isolated converter 13a corresponds to the converter B.

The bidirectional AC / DC inverter 12 has a well-known structure, and one side is connected to an AC power source 11 (for example, 50 Hz), and the other side is connected to a DC power source (in this embodiment, bidirectional high-frequency isolated converters 13 and 13a). Thus, the one whose operation is changed between AC / DC by the external signals of charge and discharge generated from the control device 18 is used. The temporal change in the direction and magnitude of the current in this case is as shown in FIG. 2 and can be switched almost instantaneously.

The bidirectional high-frequency isolated converters 13 and 13a have a well-known structure and have inverters 19 and 19a that use DC as a power source on the primary side and the secondary side, respectively. Coupled by the transformer 20 and rectified by a diode connected to the inverters 19 and 19a, a DC output is generated on the secondary side and the primary side. The bidirectional high frequency insulated converters 13 and 13a are characterized in that the intermediate part is insulated from the primary side and the secondary side by a transformer 20 in a DC manner. The conversion direction is switched by a signal from the control device 18.

The operation of the bidirectional high-frequency isolated converters 13 and 13a is shown in FIG. 3. From a state where power running (charging, applying power to the secondary side) is performed, regeneration (discharging, applying power to the primary side) or When switching in the reverse direction, it is necessary to completely stop the flow of the transistor (an example of the switching element) and the diode, and a stop time (usually 10 to 20 ms) is required.

The bidirectional DC / DC chopper 16 converts the voltage on one side (DC bus side) to the other side by converting the voltage, and obtains an appropriate voltage (for example, 500 V) for charging the secondary battery 14. Conversely, the power of the secondary battery 14 is transformed and transmitted to the primary side. The switching operation at this time is performed by a signal from the control device 18, and the operation can be instantaneously switched without requiring a certain stop time as shown in FIG.

The capacitor 17 provided in the DC bus 15 compensates for the voltage drop of the DC bus 15 that occurs during charging from the charging of the secondary battery 14 or charging from the discharging, and also absorbs sudden voltage changes.

The switching operation from charging to discharging of the bidirectional battery bidirectional power supply device 10 will be described with reference to FIGS. In this embodiment, as shown in FIG. 4 a and FIG. 5 a, a bidirectional high-frequency isolated converter (hereinafter sometimes simply referred to as “high-frequency isolated converter” or “converter”) 13, 13a is connected in parallel, the bidirectional AC / DC inverter 12, the two converters 13 and 13a, and the bidirectional DC / DC chopper 16 are set to the charging side, and the secondary battery 14 is supplied with power from the power source 11 to be charged. .

When starting preparation for discharging the secondary battery 14, as shown in FIG. 4b and FIG. 5b, the high-frequency isolated converter 13a is stopped and only the high-frequency isolated converter 13 is operated (forward operation). Then, the secondary battery 14 is charged. In this case, since power is supplied only from one of the high-frequency isolated converters 13, the supply power is insufficient, the voltage of the DC bus 15 gradually decreases, the electric charge of the capacitor 17 is discharged, and the bidirectional DC / DC chopper 16 Although the supply voltage is not extremely lowered, the charging of the secondary battery 14 is continued.

Next, as shown in FIG. 4 c and FIG. 5 c, the high frequency insulation type converter 13 is stopped and the high frequency insulation type converter 13 a is operated (reverse operation) with the regeneration side. In this case, the high-frequency isolated converter 13a takes a necessary stop period, and thus this regenerative operation is possible. As a result, the electric power from the secondary battery 14 is regeneratively discharged via the bidirectional DC / DC chopper 16, and the voltage of the DC bus 15 (that is, the capacitor 17) gradually increases. Then, after the high frequency isolation converter 13 is stopped, both the high frequency isolation converters 13 and 13a start a regenerative operation (reverse operation) as shown in FIG. Becomes normal.

For comparison, FIG. 5 shows a voltage change at the time of switching from charging to discharging according to the conventional method when there is one bidirectional high-frequency isolated converter, and the secondary battery 14 is switched from charging to discharging at time h. However, since the bidirectional high frequency insulated converter is stopped, the bidirectional DC / DC chopper 16 is operating, so that electric charge is accumulated in the capacitor 17 and the voltage of the capacitor 17 rises. Since the bidirectional high-frequency isolated converter starts operating at time i, the electric charge of the capacitor 17 is gradually discharged and returns to the original voltage at time j.

Since this test is instantaneous switching from charging to discharging of the secondary battery 14, the bidirectional DC / DC chopper 16 switches in a short time as shown in FIG. In addition, since the terminal voltage of the capacitor 17 becomes high and a large amount of the capacitor 17 is required, this problem can be solved by dividing the bidirectional high-frequency isolated converter into two and sequentially operating them.

6A to 6D show the operation when the secondary battery 14 is switched from the discharged state to the charged state, and FIGS. 7A to 7D show changes in the DC bus voltage corresponding to the operation. In the state of (b), the high frequency insulated converter 13a is stopped and the one-side state regeneration (forward operation) is performed, so that the voltage of the capacitor 17 rises. In this case, since the bidirectional high-frequency isolated converter 13 is operating, the voltage of the capacitor 17 is 1.3 times or less than the normal voltage and does not become a high voltage. Then, when the power running operation (reverse operation) is performed only with the high-frequency isolated converter 13a on one side of FIG. 6c, the current on the bidirectional DC / DC chopper 16 side is larger than that on the supply side, so the voltage of the capacitor 17 gradually decreases. .

Here, in the conventional method using one bidirectional high frequency insulated converter, the bidirectional high frequency insulated converter is stopped at time q as shown in FIG. In this case, since the bidirectional DC / DC chopper 16 is switched to the charged state, the voltage of the capacitor 17 gradually decreases. When the bidirectional high-frequency isolated converter starts powering operation at time r, the voltage of the capacitor 17 gradually increases and returns to the normal value. In this case, since the operation of only the capacitor 17 is continued, a large-capacity capacitor 17 is required in the prior art, but in this embodiment, one of the bidirectional high-frequency isolated converters 13 and 13a is operated. Therefore, the capacity of the capacitor 17 can be small.

As described above, when the secondary battery 14 is charged to discharged, or discharged to charged, the control device 18 performs the bidirectional AC / DC operation so as to perform the operations shown in FIGS. 4a to 4d or 6a to 6d. Programmed control means are provided for providing switching signals to the DC inverter 12, bidirectional high frequency isolated converters 13, 13a, and bidirectional DC / DC chopper 16.

Subsequently, a bidirectional battery power supply device 23 according to another embodiment of the present invention will be described with reference to FIG. In addition, the same component as the bidirectional power supply device 10 for secondary batteries is attached with the same number, and detailed description is omitted.
The secondary battery bidirectional power supply device 23 includes a bidirectional AC / DC inverter 12 connected to the power supply 11 and a plurality (two in this embodiment) connected in parallel to the bidirectional AC / DC inverter 12. ) Bidirectional high frequency isolated converters 25 and 26 (an example of converters C and D), a bidirectional DC / DC chopper 27 connected to the bidirectional high frequency isolated converters 25 and 26, and a bidirectional high frequency isolated converter 25. , 26 and a bidirectional DC / DC chopper 27, a capacitor 29 connected to a direct current bus 28, and these control devices 30.

In this embodiment, at least two sets of bidirectional high-frequency isolated converters are provided in one secondary battery bidirectional power supply device 23, and one bidirectional high-frequency isolated converter 26 (equivalent to converter D) is always used. When the bidirectional high-frequency isolated converter 25 (corresponding to the converter C) is stopped and the secondary battery 14 is switched from charging to discharging or vice versa, the bidirectional AC / DC inverter 12 and the bidirectional DC / DC chopper 27 are connected. While switching from charging to discharging or in the reverse direction, the bidirectional high-frequency isolated converter 26 is switched to the bidirectional high-frequency isolated converter 25. As a result, the voltage of the DC bus 28 does not drop, so that the operation from charging to discharging or vice versa can be performed smoothly. Therefore, one converter is always in a pause.

In this case, the capacitor 29 may be small in size as long as it has a capacity to compensate for noise generated at the time of switching or instantaneous interruption.
In this embodiment, the number of bidirectional high-frequency isolated converters is two, but it may be three or more, and one or half of them may be a converter that is always at rest. The control device 30 is provided with programmed control means for providing a switching signal to the bidirectional AC / DC inverter 12, the bidirectional high frequency insulated converters 25 and 26, and the bidirectional DC / DC chopper 27.

The present invention is not limited to the above-described embodiments, and there may be improvements, increases in equipment, and the like without changing the gist of the present invention.
A well-known bridge converter can be used instead of the bidirectional high-frequency isolated converter of the above embodiment.

10: Bidirectional power supply device for secondary battery, 11: Power supply, 12, Bidirectional AC / DC inverter, 13, 13a: Bidirectional high frequency insulated converter, 14: Secondary battery, 15: DC bus, 16: Bidirectional DC / DC chopper, 17: capacitor, 18: control device, 19, 19a: inverter, 20: transformer, 23: bidirectional power supply device for secondary battery, 25, 26: bidirectional high frequency insulated converter, 27: bidirectional DC / DC chopper, 28: DC bus, 29: capacitor, 30: controller

Claims (4)

A plurality of converters composed of bidirectional high-frequency isolated converters or bridge converters that require a stop period in switching, and a bidirectional chopper connected to the converter, and switches between charging and discharging of the secondary battery In the bidirectional power supply for secondary batteries,
Converter A and converter B obtained by dividing the converter into two parts;
A capacitor provided between the converter and the bidirectional chopper;
At the time of switching between charge and discharge, 1) process 2 for stopping the converter B while maintaining the forward operation of the converter A 1, 2) process 2 for stopping the converter A and causing the converter B to perform reverse operation; 3) A bi-directional power supply device for a secondary battery, comprising control means for sequentially performing a process 3 for reversely operating the converter A. A plurality of converters composed of bidirectional high-frequency isolated converters or bridge converters that require a stop period in switching, and a bidirectional chopper connected to the converter, and switches between charging and discharging of the secondary battery In the bidirectional power supply for secondary batteries,
A converter C that is one of the converters and is normally stopped;
A converter D other than the converter C;
When the secondary battery connected to the converter D is switched from the forward operation to the reverse operation, the secondary battery is provided with control means for stopping the converter D and reversely operating the converter C. Directional power supply. It has a plurality of converters consisting of bidirectional high-frequency isolated converters or bridge converters that require a stop period in switching, and a bidirectional chopper connected to the converter, and switches between charging and discharging of the secondary battery. In the control method of the bidirectional battery power supply device to be performed,
A capacitor is provided between the converter and the bidirectional chopper, and the converter is divided into a converter A and a converter B,
Further, when switching between charging and discharging, 1) the first step in which the converter A stops the converter B while maintaining the state, and 2) the converter A is stopped and the converter B is operated in reverse. A control method for a bidirectional power supply device for a secondary battery, comprising a second step and 3) a third step of reversely operating the converter A. A plurality of converters composed of bidirectional high-frequency isolated converters or bridge converters that require a stop period in switching, and a bidirectional chopper connected to the converter, and switches between charging and discharging of the secondary battery In the control method of the bidirectional power supply for the secondary battery,
One of the converters is a converter C that is always stopped,
When the secondary battery connected to the converter D other than the converter C is switched from the forward operation to the reverse operation, the converter D is stopped and the converter C is operated reversely. Control method for directional power supply.

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