JP3378562B2 - Single-phase three-wire AC / DC bidirectional converter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single- phase three-wire AC / AC which converts power energy between AC power and DC power bidirectionally with high efficiency and low distortion rate by using a single main circuit.
It relates to a DC bidirectional converter. In particular, it targets devices that charge and discharge various batteries with low loss, and the most typical example is the use of night power to store power during the daytime in order to level the power of day and night, which has recently become a hot topic. Technology related to power regeneration.

[0002]

2. Description of the Related Art The effective utilization of electric power energy has become a global problem nowadays, and in particular, the imbalance between the power supply and distribution system during the day and night is one of the causes of the decrease in the utilization rate of power generation equipment.

Even in Japan, electric power companies are trying to equalize daily power consumption by setting the late-night power charge system to about 1/3 during the daytime for ordinary households. Needs to develop an inexpensive energy storage device.

The most commonly used method for storing electric power at night and regenerating it in the daytime is to convert AC to DC once, charge the battery, and regenerate the charged electric power to the AC side. However, it is also necessary to extend the life of the battery itself and make it economical, and also rationalize and make economical the AC / DC and DC / AC converters.

[0005]

FIG. 10 is a block diagram showing a schematic configuration of a conventional charging / discharging device. As shown in FIG. 10, conventionally, an AC / DC charger 31 for charging and a DC / AC inverter 32 for regenerating electric power are separately provided. For this reason, the equipment cost becomes high, which is also a factor that hinders miniaturization.

In particular, the conventional AC / DC charger is composed of a PWM control technique using a rectifying bridge and a semiconductor switch,
It can be made smaller than a DC / AC inverter of the same capacity and can be realized at low cost, but an input current sine wave charger with harmonics of the power supply has the same capacity and cost as an inverter of the same capacity. ing.

However, conventionally, in order to perform charging / discharging, it was necessary to separately provide both the DC / AC inverter and the charger, so that there was a problem that the charging / discharging device could not be downsized and the cost was increased. It was

The present invention has been made in view of the above circumstances, and an object thereof is to provide a single- phase three-wire AC / DC bidirectional converter that can be miniaturized and realized at low cost. is there.

In order to solve the above-mentioned problems, the present invention is a single-phase three-wire AC having a noise filter connected to first to third AC terminals and a capacitor forming a part of this noise filter. A power source, first and second switching elements connected in series between both ends of a chargeable and dischargeable battery, third and fourth switching elements connected in series between both ends of the battery, and the first and second A first inductor element connected between a connection point of a second switching element and a terminal of the single-phase three-wire AC power supply, a connection point of the third and fourth switching elements, and the single-phase three-wire type A second inductor element connected to a terminal of the AC power source, a first diode connected in parallel to the first switching element, and a second inductor element connected in parallel to the second switching element. And the odd, and the third third diode connected in parallel to the switching element, the fourth
A fourth diode connected in parallel to the switching element, a first capacitor element connected across the battery, and a second capacitor connected between one end of the battery and a neutral wire.
A capacitor element, a third capacitor element connected between the other end of the battery and a neutral wire, a fifth diode connected between one end of the battery and a neutral wire, Between a sixth diode connected between the other end of the battery and the neutral wire, a connection point of the fifth and sixth diodes, and a connection point of the second and third capacitor elements And a control circuit for controlling ON / OFF of the first to fourth switching elements and the switch, the control circuit, when charging the battery,
During the positive half cycle of the single-phase three-wire AC power supply, the second switching element is turned on and off, and during the negative half-cycle of the single-phase three-wire AC power supply, the first switching element is turned on and off. ON / OFF control of the switching element, and at the time of power regeneration to the side of the single-phase three-wire AC power source due to discharge of the battery, ON / OFF control of the first and second switching elements is performed to control the positive phase. A sine wave voltage is supplied between the first and second AC terminals, and the third and fourth switching elements are controlled to be turned on / off to supply a negative phase sine wave voltage to the second and third AC terminals. Supply between terminals.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A single- phase three-wire system A according to the present invention will be described below.
The C / DC bidirectional converter will be specifically described with reference to the drawings. INDUSTRIAL APPLICABILITY The present invention uses a single main circuit connected to an AC power source of a single-phase three-wire system (in Japan, 100V + 100V, both ends of 200V) that has become standard in domestic households, and this main circuit is charged with an input current. It operates as a sine wave (countermeasure against harmonics) charger, and operates as a single-phase three-wire sine wave inverter during discharge (power regeneration).

(First Embodiment) FIG. 1 is a circuit diagram of a first embodiment of a single- phase three-wire AC / DC bidirectional converter according to the present invention, and FIG. 2 is a single-wire three-wire AC / DC according to the present invention. It is a conceptual diagram of a bidirectional converter.

As shown in FIG. 2, the single- phase three-wire AC / DC bidirectional converter of this embodiment has an AC / DC charger for charging and a DC / AC inverter for regenerating power as one unit. A feature is that the circuit 20 is connected to a single-phase three-wire type AC power supply 21.

The single- phase three-wire AC / DC bidirectional converter of FIG. 1 has first to third AC terminals TP1, TP2, TP3.
A single-phase three-wire AC power supply 2 having a noise filter 1 connected to the capacitor 1, and capacitor elements C1 and C2 forming a part of the noise filter 1, a chargeable / dischargeable battery 3, and between both ends of the battery 3. First and second switching elements Q1 and Q2 connected in series, and third and fourth switching elements Q3 and Q4 connected in series between both ends of the battery 3,
The first connected between the connection point of the first and second switching elements Q1 and Q2 and the terminal of the single-phase three-wire AC power supply 2
Of the first switching element Q1 and the second reactor L2 connected between the connection point of the third and fourth switching elements Q3 and Q4 and the terminal of the single-phase three-wire AC power supply 2 A first diode D1 connected between the source terminal and the drain terminal, a second diode D2 connected between the source terminal and the drain terminal of the second switching element Q2, and a source terminal of the third switching element Q3. And a third diode D3 connected between the drain terminals, a fourth diode D4 connected between the source terminal and the drain terminal of the fourth switching element Q4, and high-frequency noise connected across the battery 3. The first capacitor element C3 for absorption and the + of the battery 3
A second capacitor element C4 connected between the end and the neutral wire NL, a third capacitor element C5 connected between the other end of the battery 3 and the neutral wire NL, and a + of the battery 3. A fifth diode D5 connected between the end and the neutral line NL; a sixth diode D6 connected between the other end of the battery 3 and the neutral line NL; and a fifth and a sixth diode D6. Turning on the switch 4 connected between the connection point of the diodes D5 and D6 and the connection point of the second and third capacitor elements C4 and C5, and the first to fourth switching elements Q1 to Q4 and the switch 4 A control circuit 5 for controlling the off state is provided.

First to third AC terminals TP1, TP2, T
For example, AC0V, 100V, and 200V are applied to P3, respectively. The first and second reactors L1 and L2 are
It acts as a boost chopper reactor during charging and as a sine wave inverter filter during power regeneration (discharge).

First to fourth switching elements Q1 to Q4
And the first to fourth diodes D1 to D4 respectively connected in parallel to these switching elements act as a high power factor rectifier during charging and act as a bridge inverter 10 during power regeneration.

Fifth and sixth diodes D5, D6
Is between the input power terminals TP1 and TP2, or TP2 and T
When charging only with the voltage between P3, diode D1-D
Instead of 4, it plays the role of passing an electric current.

Second and third capacitor elements C4, C
Reference numeral 5 is a large-capacity electrolytic capacitor, which is provided to reduce the DC output ripple during single load operation without using the battery 3. The switch 4 is turned off during charging and turned on during power regeneration (discharging).

As the operation during charging of the single- phase three-wire AC / DC bidirectional converter shown in FIG. 1, the first and second switching elements Q1 and Q2 are on / off controlled to perform charging, and the second and second switching elements Q1 and Q2 are charged. There is a case where the fourth switching elements Q2 and Q4 are on / off controlled to perform charging.

In the present embodiment, a case will be described in which the first and second switching elements Q1 and Q2 are on / off controlled to perform charging. FIG. 3 is a diagram showing by arrows the current paths when TP1 is a positive half cycle with respect to TP2.
When the second switching element Q2 is turned on, the first reactor L1, the second transistor Q2, the fourth diode D4, and the second
A current flows through the reactor L2 and the energy is accumulated in the first and second reactors L1 and L2.

When the second switching element Q2 is off, the first and second reactors L1 and L2 try to flow current in the same direction, so that the first and second reactors L1 and L2, as shown by the dotted arrow in the figure, A current flows through the first reactor L1, the first diode D1, the second and third capacitor elements C4 and C5 and the battery 3, the fourth diode D4, and the second reactor L2.

On the other hand, FIG. 4 is a diagram showing by arrows the current paths in the negative half cycle. First switching element Q1
When is on, as indicated by the solid arrow in FIG.
A current flows through the reactor L2, the third diode D3, the first switching element Q1, and the first reactor L1.

When the first switching element Q1 is off, the second reactor L2, the third diode D3, the second and third capacitor elements C4, as shown by the dotted arrow in FIG. A current flows through C5, the battery 3, the second diode D2, and the first reactor L1.

As described above, since the current flows in the same direction in the battery 3 during both the positive cycle and the negative cycle, it is possible to perform charging with a high power factor.

FIG. 5 is a block diagram showing an example of the internal configuration of the control circuit 5 shown in FIGS. As shown, the control circuit 5
Are diodes D11 to D16, filters 11 and 12,
Step-up type power factor correction dedicated IC (PFC-IC) 13, current transformers 14, 15 and 16, operational amplifiers OP1 and OP2, inverters IV1 to IV6, a clamp circuit 17, a charge / discharge switch 18, and a logic Gates G1 to G13 and drive circuit 19
23, a switching power supply control PWM-IC 24, a diode bridge 25, an analog multiplier 26, a triangular wave generator 27 for generating a triangular wave, and comparators 28 and 29,
The power supply module 30 supplies a power supply voltage to the drive circuits 19 to 23.

The current transformer 14 detects the current flowing through the first reactor L1 and the current transformer 15 detects the current flowing through the second reactor L2. Current transformer 14, 15
Operates every half cycle of the input AC signal.
The outputs of the current transformers 14 and 15 are amplified by the operational amplifiers OP1 and OP2, and then ORed by the diodes D13 and D14 and applied to the current detection terminal of the PFC-IC13.

The reference input sine wave is a diode D1.
Two-phase half-wave rectification by 5, D16, PFC through resistor R1
-Supplied to the multiplier built in IC13. PFC-IC13
With the output pulse width of, the input current waveform is controlled so as to approach a sine wave.

During charging, the output contact of the charge / discharge switch 18 is switched to the C side, and the output of the inverter IV6 becomes high level. Therefore, the outputs of the logic gates G1 to G4 are all at the high level. Logic gates G8 and G9
Is the inverted signal of PFC-IC13 output signal PFC-PWM / P
It becomes FC-PWM (negative signal of PFC-PWM signal), and the output of logic gates G5 and G6 is the same signal as the output of PFC-IC13.
Becomes PWM. Further, the outputs of the logic gates G12 and G13 become low level.

Therefore, the first and second switching elements Q1 and Q2 are turned on / off according to the output signal PFC-PWM of the PFC-IC 13, and the third and fourth switching elements Q3 and Q4 are always off. become. More specifically, during the positive half cycle, the battery 3 is charged by turning on / off the second switching element Q2 as shown in FIG. 3, and during the negative half cycle, as shown in FIG. Thus, the battery 3 is charged by turning on / off the first switching element Q1.

In FIGS. 3 and 4, an example in which the first and second switching elements Q1 and Q2 are on / off controlled to perform charging has been described, but the second and fourth switching elements Q2 and Q4 are turned on. -You may charge by controlling the off.

On the other hand, FIG. 6 and FIG. 7 are diagrams showing the current path at the time of power regeneration by arrows, FIG. 6 shows the current path in the positive half cycle, and FIG. 7 shows the current path in the negative cycle. ing.

When power is regenerated, the switch 4 is always set to the ON state. During the positive cycle, terminals TP1 and TP2
In between, a current flows through the first switching element Q1, the first reactor L1, and the switch 4, as indicated by the one-dot chain line arrow in FIG. Also, terminals TP2 and TP3
In between, a current flows through the second reactor L2, the fourth switching element Q4, and the switch 4, as indicated by the two-dot chain line arrow in FIG.

On the other hand, during the negative half cycle, the terminals TP1,
Between TP2, as shown by the one-dot chain line arrow in FIG.
A current flows through the switching element Q2, the switch 4, and the first reactor L1. Also, the terminals TP2,
Between TP3, as shown by the two-dot chain line arrow in FIG.
A current flows through the reactor L2, the switch 4, and the third switching element Q3.

FIG. 8 is a diagram showing switching timings of the first to fourth switching elements Q1 to Q4 during power regeneration.
During power regeneration, the charging / discharging changeover switch 18 of FIGS. 6 and 7 is switched to the D side. Therefore, the inverter I
The output of V6 is "0", the output of the inverter IV2 is "1", and the outputs of the logic gates G4, G8, G9 are "1".

The reference sine wave that has passed through the insulation / distortion removal filter 11 is applied to the X terminal of the multiplier 26. Also,
This reference sine wave is rectified and smoothed by the diode bridge 25.

The outputs of the AC current detectors 14 and 15 are supplied to the anode terminals of the diodes D11 and D12 via the operational amplifiers OP1 and OP2. From the cathode terminals of the diodes D11 and D12, the logical sum signals of the outputs of the alternating current detectors 14 and 15 are output.

The PWM-IC 24 outputs a pulse modulation signal for constant voltage / constant current control based on the voltage signal rectified and smoothed by the diode bridge 25 and the current detection signal. This is converted to direct current by a filter and input to the Y terminal of the multiplier 26. The reference sine wave signal amplitude applied to the multiplier 26 is controlled by the DC voltage at the Y terminal, and outputs a reference sine wave signal having an amplitude suitable for the inverter output, voltage and current during power regeneration.

The comparators 28 and 29 compare the triangular wave signal output from the triangular wave oscillator 27 and the amplitude-controlled reference sine wave signal, and output a pulse signal according to the comparison result, as shown in FIG. . The inverters IV4 and IV3 output inverted signals of the pulse signals output from the comparators 28 and 29, respectively. Outputs of comparators 28 and 29 and inverter I
The outputs of V4 and IV3 are input to the logic gates G1 to G4, respectively.

By such control, the pulse voltage as shown in FIG. 8 is supplied from the battery 3 side to the L1C1 and L2C2 filters, and further, through the noise filter, the single- phase three- wire AC terminals TP1 to TP3. A sine wave voltage current as shown in FIG. 8 is regenerated on the side.

The first to fourth switching elements Q1
In order to turn on / off Q4, a dead time adding circuit, a snubber circuit for removing spike pulses of the main circuit, etc. are actually required. However, in the above-described embodiment, these circuits are omitted. There is.

As described above, in this embodiment, the AC / DC charger and the DC / AC inverter are combined into one circuit,
The circuit configuration can be simplified, size reduction, price reduction, and power consumption reduction can be achieved as compared with the related art. Further, by controlling the ON / OFF of the first to fourth switching elements Q1 to Q4, charging / discharging can be performed with high efficiency and high power factor.

(Second Embodiment) In the above-described first embodiment, an example in which the first and second switching elements Q1 and Q2 are on / off-controlled to perform charging has been described. The switching elements Q2 and Q4 of No. 4 may be controlled to be turned on / off to perform charging.

The second embodiment is common to the first embodiment except that the configuration of the control circuit 5 is partly different from that of the first embodiment. Therefore, the difference will be mainly described below.

FIG. 9 shows a single- phase three-wire AC / DC according to the present invention.
It is a circuit diagram of 2nd Embodiment of a bidirectional converter. In the circuit diagram of FIG. 9, arrows indicate current flows during charging and in negative cycles. The control circuit 5a shown in FIG. 9 does not include the logic gate G7 in the subsequent stage of the logic gate G5,
It is characterized in that the logic gate G13 is omitted.

In FIG. 9, the fourth switching element Q
When 4 is on, a current flows through the second reactor L2, the fourth switching element Q4, the second diode D2, and the first reactor L1.

When the fourth switching element Q4 is off, a current flows through the second reactor L2, the third diode D3, the battery 3, the second diode D2, and the first reactor L1. .

During the positive half cycle, the battery 3 is charged by controlling the ON / OFF of the second switching element Q2 as in the case of FIG. Further, at the time of power regeneration, the battery 3 is discharged by performing on / off control of the first to fourth switching elements Q1 to Q4, as in FIGS. 6 and 7.

As described above, also in the second embodiment, as in the first embodiment, the AC / DC charger and the DC / AC inverter are integrated into one circuit for charging / discharging. The price can be reduced and the power consumption can be reduced.

In each of the above-described embodiments, the circuit configuration of the control circuits 5 and 5a is not limited to the illustrated one.
The first to fourth switching elements Q at the timing described above.
The specific circuit configuration does not matter as long as the circuit can control ON / OFF of 1 to Q4.

[0049]

As described in detail above, according to the present invention, charging of a battery from a single-phase three-wire AC power supply and regeneration of power to the single-phase three-wire AC power supply by discharging the battery can be achieved. Since it can be realized with one circuit, it is possible to achieve smaller size, lower price, and lower power consumption than ever before. Further, using the present invention, if the battery is charged with inexpensive electric power at night,
It is possible to achieve leveling of power during the day and night. Therefore, if the single-phase three-wire charging / discharging device according to the present invention is introduced into a general household,
The power cost of each household can be suppressed, and stable power supply and effective use can be achieved.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment of a single- phase three-wire AC / DC bidirectional converter according to the present invention.

FIG. 2 is a conceptual diagram of a single- phase three-wire AC / DC bidirectional converter according to the present invention.

FIG. 3 is a diagram showing by arrows the current path in a positive half cycle.

FIG. 4 is a diagram in which a current path in a negative half cycle is indicated by an arrow.

FIG. 5 is a block diagram showing an internal configuration of the control circuit shown in FIGS.

FIG. 6 is a diagram showing by arrows the current paths in a positive half cycle during power regeneration.

FIG. 7 is a diagram showing, by arrows, a current path in a negative half cycle during power regeneration.

FIG. 8 shows first to fourth switching elements Q during power regeneration.
The figure which shows the switching timing of 1-Q4.

FIG. 9 is a circuit diagram of a second embodiment of a single- phase three-wire AC / DC bidirectional converter according to the present invention.

FIG. 10 is a block diagram showing a schematic configuration of a conventional charging / discharging device.

[Explanation of symbols]

1 noise filter 2 Single-phase three-wire type AC power supply 3 batteries 4 switches 5 control circuit Q1 First switching element Q2 Second switching element Q3 Third switching element Q4 Fourth switching element L1 first reactor L2 Second reactor D1 First diode D2 Second diode D3 Third diode D4 Fourth diode D5 Fifth diode D6 Sixth diode C3 first capacitor element C4 second capacitor element C5 Third capacitor element

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H02J 3/32 H02J 3/38 H02M 7/12

Claims (5)

(57) [Claims] 1. A single-phase three-wire AC power supply having a noise filter connected to first to third AC terminals, and a capacitor forming a part of the noise filter, and between both ends of a rechargeable battery. First and second switching elements serially connected to each other, third and fourth switching elements serially connected between both ends of the battery, a connection point of the first and second switching elements, and the single switching element. A first inductor element connected between the terminals of the three-phase three-wire AC power supply, and a connection point between the third and fourth switching elements and the terminal of the single-phase three-wire AC power supply. A second inductor element; a first diode connected in parallel with the first switching element; a second diode connected in parallel with the second switching element; and a third switching element A third diode connected in parallel to the child, a fourth diode connected in parallel to the fourth switching element, a first capacitor element connected across the battery, and one end of the battery A second capacitor element connected between the neutral line and a third capacitor element connected between the other end of the battery and the neutral line; and one end of the battery and the neutral line. A fifth diode connected in between, a sixth diode connected between the other end of the battery and a neutral wire, a connection point of the fifth and sixth diodes, the second diode
A switch connected between the connection point of the third capacitor element and the connection point of the third capacitor element; and a control circuit for controlling ON / OFF of the first to fourth switching elements and the switch, When charging the battery, the single-phase three-wire AC power supply controls the second switching element to be turned on / off during a positive half cycle, and the single-phase three-wire AC power supply has a negative half-cycle. ON / OFF control of the first switching element is performed during a cycle, and at the time of power regeneration to the single-phase three-wire AC power supply side due to discharge of the battery, the first and second switching elements are turned on. -Off control is performed to supply a positive phase sine wave voltage between the first and second alternating current terminals, and on / off control is performed for the third and fourth switching elements to generate a negative phase sine wave voltage. The second and Single-phase three-wire AC / DC bidirectional converter and supplying between 3 the AC terminal. 2. The control circuit, when charging the battery, and when the single-phase three-wire AC power supply turns on the second switching element during a positive half cycle, Inductor element, the second
A current is caused to flow through the switching element, the fourth diode and the second inductor element, and the second phase is applied during charging of the battery and during the positive half cycle of the single-phase three-wire AC power supply. When the switching element is turned off, the first inductor element and the first inductor element
The single-phase three-wire AC / DC bidirectional converter according to claim 1, wherein a current is caused to flow through the diode, the battery, the fourth diode, and the second inductor element. 3. The control circuit, when the battery is being charged and when the single-phase three-wire AC power supply turns on the first switching element during a negative half cycle, Inductor element, the third
Diode, the first transistor and the first transistor
When a current is caused to flow through the inductor element and the first switching element is turned off during the negative half cycle of the single-phase three-wire AC power source, the second inductor element and the third inductor element The single-phase three-wire AC / DC bidirectional converter according to claim 1, wherein a current is caused to flow through the diode, the battery, the second diode, and the first inductor element. 4. A single-phase three-wire AC power supply having a noise filter connected to the first to third AC terminals and a capacitor forming a part of the noise filter, and between both ends of a chargeable / dischargeable battery. First and second switching elements serially connected to each other, third and fourth switching elements serially connected between both ends of the battery, a connection point of the first and second switching elements, and the single switching element. A first inductor element connected between the terminals of the three-phase three-wire AC power supply, and a connection point between the third and fourth switching elements and the terminal of the single-phase three-wire AC power supply. A second inductor element; a first diode connected in parallel with the first switching element; a second diode connected in parallel with the second switching element; and a third switching element A third diode connected in parallel to the child, a fourth diode connected in parallel to the fourth switching element, a first capacitor element connected across the battery, and one end of the battery A second capacitor element connected between the neutral line and a third capacitor element connected between the other end of the battery and the neutral line; and one end of the battery and the neutral line. A fifth diode connected in between, a sixth diode connected between the other end of the battery and a neutral wire, a connection point of the fifth and sixth diodes, the second diode
A switch connected between the connection point of the third capacitor element and the connection point of the third capacitor element; and a control circuit for controlling ON / OFF of the first to fourth switching elements and the switch, When charging the battery, the single-phase three-wire AC power supply controls the second switching element to be turned on / off during a positive half cycle, and the single-phase three-wire AC power supply has a negative half-cycle. ON / OFF control of the fourth switching element is performed during a cycle, and at the time of power regeneration to the single-phase three-wire AC power supply side due to discharge of the battery, the first and second switching elements are turned on. -Off control is performed to supply a positive phase sine wave voltage between the first and second alternating current terminals, and on / off control is performed for the third and fourth switching elements to generate a negative phase sine wave voltage. The second and Single-phase three-wire AC / DC bidirectional converter and supplying between 3 the AC terminal. 5. The second inductor when the control circuit turns on the fourth switching element during a negative half cycle of the single-phase three-wire AC power supply during charging of the battery. An element, the fourth switching element,
A current is caused to flow through the second diode and the first inductor element, and the fourth switching element is turned off during the negative half cycle of the single-phase three-wire AC power supply; 2 inductor element, said 3rd
5. The single-phase three-wire AC / DC bidirectional converter according to claim 4, wherein a current is caused to flow through the diode, the battery, the second diode, and the first inductor element.